NIMR Reports is a Fan Fiction Magazine on the World Wide Web for Voyage to the Bottom of the Sea starring Richard Basehart and David Hedison

The Serpent

by Rachel Howe

The headquarters of the Secret Police stood on the Street of Pearl-Fishers, near enough to the waterfront for the damp breeze that flapped the defaced posters on the walls to carry a hint of the open sea. The building itself, a relic of the old colonial days, was an over-ornamented four-storey pile of stone that had once been white. It was now mostly a dirty brown, except where thick layers of pigeon and seagull droppings whitened the ledges.

Clinging to a carved wreath twenty feet above the cobbles, Lee Crane edged another yard along the ledge that ran between the first and second stories. The stone, slippery with guano and rotten with age, was crumbling away in places; twice already he had felt a handhold disintegrate under his fingers. An easy climb, the girl had called it -- but she must be at least fifty pounds lighter than he, and probably fifteen years younger. He wondered grimly if she had ever tried it, or had only looked at the wall in daylight. The night, lit by an incongruous mixture of flickering paper lanterns and harsh electric street lamps, offered a dubious concealment but increased the difficulty of the climb. He took another sideways step, then another; a section of ledge fell away beneath his foot, leaving him for a moment hanging by his arms as the broken bit of stone splashed into a puddle. He pulled himself back to safety, hoping that the sound would not bring the night watchman to investigate. The window was only a couple of steps away; if he stretched his left hand out, pressing himself against the wall, he could touch the edge of the frame. He stretched a little farther still, and closed his fingers round an iron bar, rusty but strong enough to take at least half his weight. After that it was almost simple; in a few seconds he was in front of the small opening, clipping the rope at his waist to the one bar that was to be left intact.

"Admiral?" he called softly. "Can you hear me?"

In the darkness within, there was a sudden movement and a rattle of chains, but no other response.

"Admiral?" When there was still no answer, Crane risked a quick flash of his flashlight. There was something huddled in the far corner -- something that could have been mistaken for a bundle of dirty rags but for the gleam of eyes. "Admiral Nelson! It's me -- Lee. I've come to get you out."

The figure in the corner stirred again, feebly; for a moment the face turned to the window. In that moment Crane knew that he had the right room, but he knew also that this was going to be more difficult than he had thought. For some reason, in all the planning for this rescue, it had never occurred to him that the Admiral might be incapable of helping himself. When he saw that face, empty of recognition, of intelligence, of everything but despair, flinching away from the light, dismay knotted in his guts; the flashlight almost dropped from his suddenly clammy fingers. Mechanically, he pushed it back into his belt, brought out the miniature sonic cutter, and began to work on the bars. The iron was newer than the stonework, but still at least fifty years old, half eaten away by the moisture-laden air; the cutter sliced through each inch-thick bar in a few seconds. Within a couple of minutes, Crane had made an opening large enough to scramble through.

The cell was about ten feet square, with two walls of the original stone and two of rough plank partition; it stank of fear and blood and other things even less pleasant. Of the three sets of shackles set into the wall, only one was in use.

"Now, sir," Crane said, with a cheerfulness that sounded inane in his own ears, "let's see about getting you out of those chains."

The prisoner shrank away, crouching in the angle of the wall, hiding his eyes from the light and shuddering.

"It's all right -- I'm not going to hurt you." As gently as he could, Crane pulled Nelson's hands away from his face and began to slice through the chain of the handcuffs. The cuffs themselves would have to wait; the important thing was to get the Admiral free from the wall. Nelson struggled feebly, watching the cutters with uncomprehending, fascinated terror. As soon as he was released, he staggered to his feet and put the width of the room between himself and Crane.

"No," he said thickly, leaning against the opposite wall. "No more. No more."

"Come on," Crane said patiently. "We have to get out before the guards come. Please, Admiral, try to understand. Whatever they've done to you, it's over: we're going home."

For an instant, he thought there was a glimmer of reason in Nelson's eyes, but it vanished before he could be sure of it, quenched by a flood of animal rage.

"All right," Crane sighed, "I suppose we'll have to do this the other way." There was no time for finesse, with the guards perhaps only yards away on the other side of the locked door; he crossed the floor in two long strides and knocked the Admiral unconscious with one quick, scientific blow to the neck, then made a harness around his shoulders from the free end of the rope with a few sailor's knots. Hoping that his companions, waiting in the alley below, would understand what was happening, he pushed Nelson's inert body out through the window and lowered it slowly. He winced at the dull thuds as Nelson bumped twice against the wall; then the tension on the rope eased. Crane waited a few moments before he wriggled out of the window himself. He was only just in time; as he dropped below the window-sill, he heard the heavy tread of a guard, and then the rattle of a key in the lock. Knowing that there was no chance that the absence of the bars would go unnoticed for more than a few seconds, he slid down the first couple of fathoms of the rope, then let go and dropped the rest of the way.

"Let's get out of here," he gasped.

"This way," the girl said quickly.

"What happened to the Admiral?" demanded Chief Petty Officer Sharkey, settling Nelson's inert body over his shoulder.

"There isn't time," Crane said curtly. "Let's go."

They followed the girl down an alley that was no more than a four-foot gap between two buildings, and into a maze of lanes and passages and dark yards. Without a guide, they would soon have been lost, or trapped in a dead end, but the girl seemed to know where she was going; her slim, cloaked figure flitted ahead like a shadow. At first, the sounds of pursuing feet, shrill whistles and shouted orders, were dangerously close. Presently, however, as the fugitives plunged deeper into the oldest quarter of the town, the hunt dropped farther and farther behind.

"Let me take the Admiral now," said Crane, as they paused to catch their breath under the arch of a bridge.

"I can manage, sir," Sharkey responded stoutly. "It isn't far now, if I remember right."

"One, two more streets," the girl put in. "Come quickly."

They took the last few hundred yards at a stumbling run: at the end of the last street was a narrow stone staircase leading down to the harbour. The little sampan bobbed where they had left it, a patch of deeper darkness on the oily blackness of the water. The girl gave a soft, fluting whistle: after a moment it was echoed. Beckoning to the others, she ran lightly down the steps and disappeared under the canopy of the vessel. Sharkey followed, more slowly, careful of his burden. Crane stood for a moment, listening to the distant cries, trying to judge how long they had before the pursuers came to the stairway. It could be a couple of minutes, he decided -- long enough for the sampan to disappear among the clutter of junks and launches in the harbour.

"Well, Skipper?" Sharkey challenged, when the sampan was under way. He had laid Nelson down in the bottom of the vessel, still unconscious, and covered him with a folded sail.

"I had to knock him out," Crane confessed. "There wasn't any other way, Chief -- I had to get him out of that place, and he wasn't going to be any help. I don't know what they did to him, but there's something very wrong."

"They only had him for three days," Sharkey protested. "What could they do in that time?"

"I don't know," Crane said helplessly. "Are there any sedatives in that first aid kit? I don't want him going wild in here when he comes round."

By the inadequate lantern-light that was all they dared use, Sharkey rummaged in the first aid box and produced a loaded syringe. Nelson was already stirring weakly when Crane slid the needle into his arm; for a moment his eyes opened, staring and senseless, and his whole body tensed as if in preparation for a struggle. Then, as the drug took effect, he relaxed with a long sigh.

"That ought to keep him under for a few hours at least," Crane said with a touch of relief. "Come on -- let's get rid of the ironmongery."

The fetters were of hardened steel, and closely fitted to Nelson's wrists and ankles; what Crane had at first taken for rust turned out to be dried blood from the raw places where the skin had been rubbed through.

"Not very civilised," Sharkey observed grimly, swabbing the sores with antiseptic when the metal had been cut away. "I wonder what else they did."

"I'd like to know why," Crane countered. "He must have known the risks, but he never said anything -- I don't even know for sure what he was doing here."

"They are animals." The girl had been sitting in the stern, looking out for signs of pursuit, but now she ducked back under the canopy. "They need no reason for what they do. They are worse than the old war-lords."

Sensing something personal in her bitterness, Crane looked at her sharply. She was the ordinary foot-soldier of the resistance, a half-educated peasant girl who had chosen to live all her days in fear for the sake of a freedom she might never know. She might be even younger than he had originally thought, perhaps not yet twenty, but the grief in her eyes was as old as the sea itself.

"Lelika," he said gravely, "do you know what has been done to the Admiral?"

She turned her head away, not answering, her lip trembling as she looked down on Nelson.

"Please, Lelika. We have to know if there is any way we can help him."

"He is mad?" she asked, reluctantly meeting Crane's eyes again.

"He seems to be. Do you know what could have caused it?"

"There is a drug," the girl said after a long pause. "They use it to make their prisoners talk, but it destroys the mind. My brother . . ." She sank to her knees, brushing at her eyes as if impatient with the weakness of tears. "They caught him at the printing press, a year ago. They kept him a week, then let him go. Friends brought him home, but he knew nothing -- not who he was, or where, or who we were. After three days . . ." She stopped, fighting back sobs.

"I'm sorry," Crane said gently. "Take your time."

"After three days he killed himself," Lelika said at last. "My mother had only left him for a moment, to fetch wood for the fire."

"I'm sorry." Crane reached out and put his arm around her thin shoulders, and held her until she grew calm and pulled away.

The Resistance safe house was in a fishing village, a few miles down the coast from the town. To the casual eye, it looked exactly like all the other little houses -- a lop-sided structure of poles and woven rush mats with one stone wall at the back. Its secret was concealed under the matting floor of the main room, where a ladder led down into a spacious, watertight cellar equipped with bunk beds, an oil stove, and an ancient short-wave radio transmitter. There was even a small but adequate bathroom, put in at the insistence of -- and with funding from -- the Western agents who used the place from time to time. Lit by several kerosene lamps, the cellar seemed glaringly bright after the darkness of a village that had never heard of street lighting.

"Right," Crane said, sliding home the bolts of the trapdoor, "we'd better get him cleaned up."

"Right, sir," Sharkey responded, his face troubled. "Skipper," he added uncertainly, "what are we going to do after that? If the girl knows what she's talking about, the Admiral isn't just going to wake up in his right mind in the morning."

"We have to give him every chance we can."

Together, they stripped off the filthy remains of the Admiral's clothes, washed him thoroughly, and attended to a considerable collection of cuts and bruises, none of which seemed to be too serious. Deep in drugged sleep, Nelson stirred feebly but did not wake even at the touch of cold water or the sting of iodine on open sores. Finally, they dressed him in a clean pair of his own pyjamas and put him to bed in one of the lower bunks.

"Well," Sharkey said dubiously, straightening the blankets with unnecessary precision, "at least he looks a bit more like himself now."

"Keep an eye on him, Chief. I have to contact Seaview." From the pile of belongings stacked in the corner of the room, Crane brought out their own portable transmitter. This was a much more sophisticated model than the one provided by the Resistance, capable of sending a scrambled signal to the submarine waiting out at sea on the far side of the island, more than a hundred miles away. "Duckling to Mother," he said into the microphone, wondering, not for the first time on this trip, what had possessed him to pick such an absurd pair of code-words. "Duckling to Mother. Come in, please."

"Duckling, this is Mother. Lee, what took you so long?" The response from Chip Morton, Executive Officer of the Seaview, was sharp with the annoyance that accompanies relief.

"We ran into a few problems," Crane said wearily.

"Is the Admiral safe?"

"We got him out, but he's in bad shape, Chip. We're going to have to change our plans a little -- I don't think he'll be fit to travel tomorrow. We had a hard enough time ourselves, getting over the mountains -- there's no way we can come back the same way with a sick man on our hands." A movement on the other side of the room caught his eye: Nelson, at least semi-conscious, was trying to sit up, reaching uncertainly for the glass of water on the locker beside his bed. Sharkey gently pushed him back, then picked up the glass and gave it to him.

"What happened?" Morton asked.

"We think the secret police used some kind of interrogation drug on him. It may wear off in time, but at the moment he seems to be out of his mind. We've got him sedated for the time being. Can you come round to this side of the island and pick us up?"

"Negative, Skipper. The Western coast is all rocks and shallows: even if we could bring Seaview in, we couldn't do it without being seen. The only safe harbours are full of fishing boats."

"What about the Flying Sub?" Crane suggested, watching as Nelson drank. The glass wobbled in his shaking hand, but the level of water was dropping rapidly.

"Still out of commission, I'm afraid. The last typhoon hit us pretty hard: the repairs are going to take another couple of days at least."

"Wonderful," Crane muttered. "Well, I suppose we'll just have to --" He broke off abruptly, hearing a crunch of breaking glass and a cry from Sharkey.

"Stand by," he said hastily.

Nelson was on his feet, his eyes focussed on something beyond the walls of the cellar; blood and water ran down his raised arm and dripped on the matting of the floor. The jagged remains of the drinking-glass were still in his hand, clutched like a weapon. He lurched forward, unsteady but determined, as if seeking some desperate confrontation with whatever it was he saw.

"It's all right, Admiral," Crane said, knowing it sounded foolish. "There's nothing there. You're quite safe now." Cautiously, he reached out and took hold of Nelson's arm. "Let me have a look at those cuts." The next moment, he was on the floor, struggling for breath, with Nelson kneeling solidly on top of him. The shards of glass, edged with crimson, glittered in the lamplight; there seemed to be blood everywhere. Snarling with rage, Nelson drew back his arm for another blow. Then Sharkey caught him from behind, pinioning his arms to his sides: the Admiral struggled briefly, then went limp as shock and blood loss caught up with him. The broken glass fell from his hand and shattered against the table leg. Sharkey half-carried him back to the bunk, and left him there, then came back to kneel beside Crane.

"Skipper? Can you hear me, sir? How badly are you hurt?"

"I'm all right," Crane said shakily. "You'd better get the Admiral's hand patched up before he loses any more blood."

"Are you sure you're not hurt, Skipper? I thought he got you."

"I'm fine," Crane insisted, sitting up. "He just knocked the breath out of me." Realizing that Sharkey still looked unconvinced, he glanced down at his chest. There was certainly a great deal of blood, but only a little of it was his own; the glass had ripped his shirt and made a long, shallow cut across his ribs. "It's only a scratch. Go and see to the Admiral, Chief."

"Lee, what's happening?" Morton demanded. "Do you still read me?"

"I read you, Chip. We just had a little trouble with the Admiral, but everything's under control now. Where were we?"

"Stuck on the wrong side of the island with a dangerous lunatic," Morton replied with grim humour.

"I need to talk to the Doctor," said Crane. "Can you get him to the radio?"

"I'm right here, Captain," came the calm voice of the Seaview's doctor. "Can you give me a description of the Admiral's condition?"

"I haven't had much chance to see what he's like when he isn't sedated," Crane admitted, "but he seems to be virtually catatonic most of the time, with episodes of irrational violence and possibly hallucinations. Have you any ideas, Doc?"

"I've never heard of an interrogation drug that would produce symptoms like that," the Doctor replied, "but I'll look into it. In the meantime, try to keep him from hurting himself -- and go easy on the sedatives. If the other drug is still in his system they may do more harm than good."

"We haven't that many doses anyway," Crane responded. "All right, we'll try to save them for emergencies. You could try talking to the CIA -- their agents may have come across this stuff. They might even know of an antidote."

"I'll see what I can find out, Skipper."

"Good. Chip, how soon can you get the Flying Sub operational?"

"About thirty-six hours if we push it, sir."

"Then we'll have to sit tight for a couple of days. We can't risk it in daylight."

"I understand, Lee. Keep in touch."

"I will. Good-night, Chip."

"Skipper, does this count as an emergency?" Sharkey enquired, when Crane had shut down the radio and stowed it away.

"He doesn't look very dangerous now." Crane came over to the bunk for a closer look. Nelson lay still, breathing fast and shallowly; his lips were bluish-grey with shock. The two deep cuts across the palm of his hand still oozed blood, despite the tourniquet around his wrist.

"The tendons seem to be okay," Sharkey said, "but it's going to need stitches. If he starts thrashing around . . ."

"I'll hold him," Crane said firmly. "It's much too soon for another shot anyway -- he shouldn't even have woken up for another hour."

"Aye-aye, sir."

As it turned out, Nelson offered no resistance; he did not begin to regain consciousness until the cuts had been sutured and the hand firmly bandaged. Even when his eyes opened, he seemed too weak to be troublesome; he drank the lukewarm sugary tea which Crane offered him from a plastic cup, then lay back and dropped into an uneasy, exhausted sleep.

"You should get some rest yourself, sir," Sharkey said then. "I'll watch the Admiral for a few hours."

"All right, Chief. Wake me if anything happens, or if you start to get sleepy." After a day that had begun some twenty hours before with a mule-ride across the mountain backbone of the island, not to mention the events of the last few hours, Crane was too tired to argue. He threw himself on a bunk, rolled himself in a couple of blankets, and fell asleep almost instantly.

About two hours later, Nelson woke up, screaming unintelligibly and lashing out at invisible assailants. Fortunately there was nothing within reach that he could use for a weapon. It took the combined efforts of Crane and Sharkey to hold him still until the fit passed and he subsided, shuddering and panting, against the pillows. Afterwards, he seemed calmer, though hardly rational; it was even conceivable that he dimly understood that they meant him no harm.

In the morning, Lelika, tapping an agreed-upon code on the trapdoor, brought freshly cooked rice and a jug of fish soup. She was not much surprised to hear of the change of plan, and readily agreed to keep them supplied for another two days.

"There is something else you should know," Lelika said then, hesitating a little. "You are not the only foreigners here."

"We aren't?" Crane was surprised: the village was tiny, with little to offer to visitors even by the standards of a country which did not encourage tourism.

"There is an Englishman staying in my mother's house. He came last night, in a fishing boat. He wants us to believe he is an ordinary traveller, but I think not."

"Does he know we are here?" Crane frowned, wondering why British Intelligence would interest itself in an obscure and backward corner of the China Sea, at the same time that the Seaview had been sent there.

"No, and we will not tell him unless you wish it."

"Please don't tell him," Crane said firmly.

"Very well, Captain."

The day passed slowly; as the sun heated the stone above, the cellar grew stuffy. Nelson sat quietly for the most part, gazing into nothingness. Occasionally, expressions of anger or fear would pass over his face, like squalls on a calm ocean, and once or twice he started to his feet, but quickly subsided again. The others spoke to him from time to time, reassuring or encouraging; it seemed as futile as talking into a broken radio link. They fed him, carefully, with a wooden spoon, as one might feed an infant. As often as not, he would shy away, refusing to open his mouth; after an hour of patient coaxing, he had swallowed only a few spoonfuls.

By nightfall, Crane was beginning to think that Morton, in charge of the submarine and her crew of over a hundred men in a crowded and unfriendly sea, had the easier lot. He remembered days of life-or-death struggle that had left him less drained than this business of nursing. Just before dark, he slipped outside for a few minutes in the fresh air. The western sky still glowed with pale, nacreous sunset tints over the oyster-grey sea; far off on the horizon the fishing-boats were already showing their lights. Savouring the brief, unfamiliar tranquillity, Crane wandered along the tide-ribbed sand of the beach for several hundred yards. When he almost tripped over the man smoking a pipe in the shelter of the breakwater, it was hard to tell which of them was more startled.

"You don't look like one of the locals," the stranger remarked. Something in the tension of his pose suggested that he had a weapon within reach, and was quite prepared to use it if he had to. He spoke pleasantly enough, however, with a clear, expensive British accent that went oddly with his disreputable outfit of jeans and baggy sweater.

"No," Crane replied warily. "I'm staying with friends in the village."

"American?" The Englishman seemed to relax a little. "Not that it matters much," he added after a moment. "As far as this place is concerned, the whole world seems to be on the same side."

"That sounds like dangerous talk," Crane commented.

"It's a dangerous country for strangers," said the Englishman.

"So I hear. They say the Secret Police have some very unpleasant interrogation techniques."

"I know." The Englishman sounded abruptly solemn. "They got their claws into a colleague of mine, a while back. Our consulate made a fuss and got him out after a week or so, but he hasn't been right since. Last I heard, he was still in some kind of nursing home. Shame -- he used to be a good man."

"Is that why you're here?" Crane asked cautiously. "It's all right," he added quickly. "You don't have to tell me."

"No. My lords and masters aren't too keen on personal crusades." The Englishman knocked out his pipe against the wood of the breakwater. "I'm here because there's something going on. You see that out there?" He gestured in the direction of the darkening horizon. "That trawler, out beyond the fishing boats -- she isn't from these parts, and unless I'm much mistaken it isn't fish she's after."


"Almost certainly. Believe me, something's going to happen -- or if it isn't, there's an awful lot of misinformation about. So I'm here to report on it when it happens."

"Are you trying to make me believe you're a journalist?" Crane enquired sceptically.

"You may believe what you like," responded the Englishman. "Come to that, I doubt you are here purely for pleasure, but I shan't intrude into your business."

"I appreciate it. Well, take care. I have to be getting back."

"Well, it isn't going to be our concern, whatever it is," Morton responded when he was informed of this conversation. "Our orders now are to head straight for home as soon as you and the Admiral are aboard."

"What about the mission?" Crane demanded, a little indignant but not really surprised.

"They're making other arrangements."

"Has the Doctor gotten anywhere with his enquiries?"

"Not very far, I'm afraid. It looks as though only the CIA know anything, and it takes time to get through their clearance procedures, but we're working on it."

"If there is a cure," Crane observed gloomily, "it sounds as though British Intelligence doesn't know about it -- unless our friend really is a journalist."

The night was worse than the day, though Crane forced himself to believe that it was better than the night before. He and Sharkey took it in turns to rest; neither of them was ever able to sleep for more than a couple of hours at a stretch. Four times during the night, Nelson woke from shallow sleep in a state of desperate, almost unmanageable, terror, struggling and crying out. Each time, it was several minutes before he returned to the relative docility he had shown in the day-time. On the first two occasions it was hard to be sure whether soothing words and firm but not unkind handling had any effect at all, but the third time it did seem that Crane's voice calmed him a little. The last time, just before dawn, they were almost certain of it. For a fleeting instant, there was even something like a glimmer of recognition in his eyes, before they closed again in exhaustion.

In the morning, Lelika brought disquieting news along with the breakfast rice and fish soup.

"The Secret Police are searching the villages along the coast," she reported. "One of our young men was taken yesterday, north of the town. Perhaps they come here today. You must be careful not to be seen or heard."

"They don't know about this place?" Even with Nelson in his passive day-time state, Crane did not think much of their chances if they had to leave the cellar.

"We think not," the girl replied, but her eyes were anxious. "There is always the danger of betrayal."

"What about the Englishman?" Sharkey put in.

"He is gone," said Lelika. "Last night he went with the fishing boats again: I think he would go back to another village. There was no reason for him to stay here."

"Do you know what they're after?" Crane asked.

"Dissidents, foreigners, poets -- who knows?" The girl tossed her head in contempt. "I do not think they will go to much trouble to find your friend -- he would have been no more use to them. But they might look for those who helped him escape."

It was about noon when the Police came. Warned by a particular knock on the trapdoor from the old woman who lived in the hut above, Crane extinguished the lamps and blocked the air vent with a piece of sacking. He was worried about the effect the sudden darkness might have on the Admiral, but his fears proved groundless. Whatever stimuli governed Nelson's bizarre diurnal cycle, it appeared that external illumination had little to do with it. He stirred once or twice, during the ten minutes when booted feet stamped across the floor above, but he made no disturbance. The hiding place remained undiscovered. Later, with a surprising, almost childish excitement, Lelika recounted how she had played the part of a simple village girl and decoyed the searchers into wasting an hour turning over sacks in an innocent storage cellar at the other side of the village.

An hour or so after dark, with the Doctor's reluctant consent, they sedated Nelson in preparation for the journey. Even if the drug only held him for a couple of hours, it would be enough to get him safely aboard Seaview. When they were sure he was unconscious, they wrapped his inert body in blankets and carried him down to the little jetty where the sampan was moored.

"Maybe your friend will get well," Lelika said into the silence, while the sampan lay out in the bay waiting for the Flying Sub to arrive. "I hope so."

"Thank you," Crane said gravely. "We hope so too."

"Your craft comes," she said after a pause. "Goodbye, my friends. I have been honoured to be able to help you."

"We have been honoured by your help," Crane assured her, and Sharkey, more bashfully, mumbled something to the same effect. Lelika held out a hand, uncertainly imitating a gesture alien to her culture, then suddenly, unexpectedly, kissed them both on the cheek. A few moments later, the Flying Sub rose out of the dark water beside the sampan.

"I can't tell you much until I've had the chance to make a proper examination," the Doctor said, an hour or so later, in the Seaview's Sick Bay. "Physically, it doesn't look too bad -- none of these abrasions are infected, for a wonder, and there's no sign of any serious injuries."

"I think his mental state is improving a little," said Crane, "but I'm no expert."

"From what you say, I think you may be right." The Doctor consulted the notes he had taken of their radio conversations, then shook his head. "We'll just have to wait and see."

"He'll probably be -- difficult -- when he wakes up," Crane warned. "Let me know if you need any help.

"I'm sure that won't be necessary, Captain. You've done a good job, but now it's time to leave it to the professionals. I suggest you go and get some rest. I'll give you a full report in the morning."

"All right, Doc," Crane responded with a tired smile. "I'll go away and let you get on with your job." He did pass through the Control Room on his way to his own quarters, but Chip Morton, who obviously had everything well in hand, firmly reinforced the Doctor's advice.

"You've had enough, Lee," he said bluntly. "The Chief's probably asleep already, and so should you be. There's nothing much going on here -- you can take over in the morning."

Grumbling humorously about feeling unwanted, Crane retired to his cabin, and fell asleep within a few minutes of lying down. Three hours later, he was woken by the blaring of the intercom.

"I'm sorry, Captain." The Doctor sounded shaken. "I think you'd better come down to Sick Bay."

"The Admiral?" Crane asked blearily, looking at his watch.

"You might be able to calm him down -- I'm afraid I can't."

"All right, I'm on my way." Crane took a few seconds to splash water on his face and pick up a robe, then set off down the corridor at a run.

The scene that confronted him, when he entered the normally peaceful confines of Sick Bay, was one almost of chaos. The Admiral was backed into a corner, fending off the Doctor and a corpsman with the remains of a smashed wooden stool. His eyes were wide and terrified, seeing some horror invisible to the others.

"Get out of the way," Crane ordered. The Doctor stepped quickly aside, still clutching a broken syringe. The corpsman hesitated for a moment, then moved in the opposite direction. Nelson stayed where he was, still flailing a stool-leg like a club in each hand. It was obvious that his violence was not directed at anything real. Crane approached him, moving slowly and steadily, talking in a calm, reasonable voice. "It's all right, Admiral," he said. "You're safely back on board Seaview. We're going home." The words, or perhaps just his voice, seemed to have a little effect; Nelson lowered his hands, but his body still quivered with tension, and there was no sense in his eyes. Crane came closer, then reached out and took him gently by the shoulders. "Come on, sir," he said. "Look at me. Look around you. There's nothing here to hurt you."

He had been a long time in the dark water, drifting, drowning; sounds and images swirled past in the flood, bereft of meaning, gone before he could grasp them. He had no name, no memories, only dark and fear and pain without beginning or ending. Sometimes, the darkness pressed close, taking on the shapes of nightmare, taunting him until he fought them off. At other times, dimly, he was aware of rooms, of figures, even of voices, that did not belong to the world of the darkness. These things were never with him for long; sooner or later the black tide swept them away. While they lasted, however, the shadow-monsters would draw back a little and leave him to a kind of peace. Sometimes, also, when the monsters threatened to overcome him, when he was most deeply lost in the dark, the outside hands and voices would suddenly be there, drawing him back towards the light. He had a vague perception, too tenuous to amount to an idea, that this had not always been so; that there had been a time when the voices spoke only to drive him further into torment, when the touch of hands brought only more pain.

He had come out of one of the intervals of unknowing to find himself surrounded by the worst creatures of the dark. The room beyond them was not the place where he had been before; the voices calling to him were uncertain and unfamiliar, offering no comfort. He had to struggle alone, against a whole army of fanged and tentacled monstrosities that seemed hardly to feel the blows he aimed at them. The only possible refuge was oblivion, back in the deepest darkness, and he knew that he would have to seek it before long.

Then, beyond hope, he heard one of the familiar voices, calm and sure. The monsters shrank back, snarling their disappointment; the dark water sank as if the outlet valve of a tank had been opened. There was a face very close to his own; a pleasant face, clean-cut, with hollows of exhaustion under the eyes; a face he knew. There was even a name that belonged to the face, and with a great effort he found it.

"Lee?" he said uncertainly. The face crumpled, twisted into strange shapes by emotion, but around it the whole room sprang into focus. It was not a strange place at all, but somewhere as familiar as home. Memory returned in a vertiginous rush; for a moment he staggered, sagging against Crane's support, but then he straightened. He was himself again, Harriman Nelson, marine scientist and four-star Admiral, and he was back where he belonged, aboard his own beloved Seaview.

"Welcome back, Admiral," said Crane.

"Thanks, Lee," Nelson said slowly, still trying to sort out his recollections, to make some kind of sense out of what had happened. "Thanks for bringing me back."

"Any time, Admiral," Crane responded cheerfully. "How do you feel now?"

"How am I meant to feel?" Nelson countered. "Like waking up from a nightmare, I suppose." He looked down at his hands, carefully uncurling his fingers from the pieces of wood the corpsman was trying to take away from him. There was a heavy, bloodstained dressing on one palm, with a throbbing hurt under it, and some odd bruises and scrapes around his wrists. "What's been happening to me?"

"Come and lie down, and I'll tell you about it," Crane offered, leading him over to a bunk.

"Briefly," the Doctor warned. "It's very late, and you need to rest, Admiral."

"Not without some answers," Nelson said firmly. Now that he came to think of it, he was very tired, but he was reluctant to abandon himself to sleep. The darkness had receded for the time being, but it had not gone completely, and the monsters were still waiting somewhere below the surface of his awareness. It was pleasant, though, to lean back against the pillows. "A hot drink would be nice," he added.

"I'll see to it, sir," the corpsman said quickly.

"How much do you remember?" Crane enquired, pulling up a chair for himself.

"I remember . . . going ashore in a fishing boat," Nelson replied. "Kwaishan, wasn't it?" He frowned, puzzled. "A little fishing port on a rocky coast, a dingy room over a shop. I can't remember what I was doing there, or anything after that except . . . nightmares."

"You were on some kind of Intelligence work," Crane told him. "Even I didn't know what you were after. You went ashore ten days ago. The first four nights you called in on schedule -- just a few words to let us know you were safe, and making progress. Then you went missing. We got in touch with the local Resistance, and they told us that you'd been captured by the Secret Police and taken to their headquarters in the capital. Chief Sharkey and I went to get you out, with a lot of help from the Resistance people. It seems that the Secret Police aren't very careful with their prisoners: you were quite ill when we found you. Then we had to spend a couple of days in hiding before the Flying Sub could pick us up."

"Ill?" Nelson echoed, sensing the evasion. "Can you be a little more specific?"

Crane and the Doctor exchanged glances.

"They used a very powerful drug in the interrogation," the Doctor said carefully after a moment. "The after-effects may take some time to wear off."

"I see," Nelson said slowly. "That would explain it, I suppose." He lay quietly for a little while, pondering the implications. He felt too weary for any more answers. Then, suddenly, he tensed and started to sit up. Over by the door, something had coalesced out of the darkness -- a tall figure, vaguely man-shaped under a shaggy pelt of dripping slime. He glared at it, impatient with the intrusion, and it vanished like a pricked bubble.

"What's wrong?" Crane asked.

"It's all right," Nelson sighed. "It's gone again. Of course, it wasn't really there in the first place."

"Of course not," Crane said soothingly, but his eyes were worried. "I ought to let you rest," he added, rising.

"Please -- stay a while," Nelson begged, before he could stop himself. He knew it was absurd, but he did not want to be alone again with the creatures of his dreams. There was a spider, a good ten inches across, crouching at the foot of the bed, its eyes red and malevolent. When he kicked at it, it scurried back into the shadows. He shook his head, forcing himself to concentrate on safe, familiar realities.

"I'll stay if you need me."

"No! I've given you enough trouble already. I ought to be able to handle a few hallucinations." Nelson started violently as the door opened, but relaxed when he realized that it was only the corpsman returning with a mug of hot milk. "Go on, Lee," he said. "Go and get some sleep -- you look like you could do with it."

"The next person that tells me that," Crane said, sounding a little reassured, "is in trouble. All right, Admiral. Good night."

"There is just one more thing," Nelson said suddenly. "Just tell me that thing in the corner isn't real."

"What thing?" Crane asked, startled. "There's nothing there, sir."

"Thank you. I thought there couldn't be, but it's a little hard to be sure."

"The Admiral still isn't at all well," the Doctor informed Crane, the next morning. "Certainly he isn't fit for duty, and for the present I don't think he should be left unattended."

"But he is getting better?"

"Let's just say there's some improvement. He's more or less rational, but that's about as far as it goes. His nerves are in a terrible state, and he seems to be hallucinating most of the time. Usually he can tell what's real and what isn't, but it puts him under a lot of strain. I don't think he slept at all after you left last night"

Crane frowned. "Isn't there anything you can do to help?"

"Unfortunately, sedatives are contra-indicated," the Doctor replied, "and I can understand why. It seems that he needs to be alert to tell the difference between reality and hallucination. You told me yourself that he seemed to be calmer during the day, and I think that's still true."

"You got the information from the CIA, then?"

"Yes. There isn't much, and what there is isn't very encouraging. See for yourself, Captain."

Crane flipped through the sheaf of transcripts, which made grim reading. The drug used by the Kwaishan Secret Police, it seemed, was a rare psychotoxic compound, believed to be an extract of a local seaweed, which caused severe mental disturbance and could remain in the body almost indefinitely. Ten agents in the last five years had fallen victim to the drug. Of those, five had died within a few days of release, three by suicide and two killed in self-defense by colleagues to whom they had become unmanageably dangerous. Of the survivors, one was in an institution for the incurably insane, and three had eventually returned to civilian life but still suffered recurring episodes of mental illness. Only one had made a full, spontaneous and completely unexplained recovery. There was no known cure, and the only recommended palliatives were rest, support, and mild pain-relieving medication to deal with secondary symptoms such as headache.

"One in ten doesn't seem like very good odds," Crane remarked. "Does he know?"

"I didn't see any point in telling him," the Doctor admitted. "He has enough to contend with as it is."

"Has he remembered anything else about what happened back there?"

"Not yet. That could be quite ordinary traumatic amnesia, and it may clear up in a day or two. At the moment, the important thing is for him to get as much rest as possible. He may like to sit up in the Observation Nose for a while, later on. Could you arrange for him not to be disturbed?"

"No problem, Doc." Compared with some of the other things he had done for Nelson lately, this was easy. "Let me know when, and I'll have the area declared off limits. But if we run into any trouble, I want him safely out of the way."

"I understand, Captain."

"All right, Bradley," Nelson said to the young corpsman. "We're both agreed that there's nothing there. The only difference is, I can see something anyway. But as it isn't there, it can't do anything to me, right?"

"Right, Admiral." Bradley had no idea where this conversation was leading, and he found the Admiral's company rather unnerving.

"Right." Nelson pushed aside the picked-at remains of his breakfast and stood up. "No, I can manage," he said impatiently to Bradley, who had made as if to help him. The figure in the centre of the room waved long, clawed arms and shook its head; the long strands of its mane floated out impossibly slowly, as if it were in water rather than air. He took a few steps toward it, then stood, sceptically regarding it. "Now look here," he said reasonably. "You don't exist, and you don't scare me. If you won't go away, I shall just walk right through you, and then we'll see who's real." The creature stood its ground, its mouth opening in a silent snarl that revealed bone-white fangs more than six inches long. "All right," Nelson said grimly. He walked forward, hands at his sides, fixing his eyes on the wall beyond the monster. It backed away a little, then suddenly reared up and fell on him with the force of a breaking wave, all claws and fangs and stinging tentacles, knocking him to the floor. The darkness surged up and enveloped him.

"It's only mild shock," the Doctor, who had come out of his office at Bradley's cry of dismay, pronounced after a hasty examination. "He should come round in a few minutes. Really, Bradley, I thought you could be trusted to look after the Admiral for half an hour."

"I'm sorry, Doctor. I didn't think it could do any harm to let him try out his idea."

"Well, don't let it happen again," the Doctor snapped. "In future, don't think -- ask. Now get him back on the bed and don't let him up until I give you permission."

"I don't understand," admitted Crane, helping the corpsman to lift Nelson from the floor. "How could something that isn't even real do this to him?"

"Obviously it is real to him," the Doctor said thoughtfully, "even though the rational part of his mind knows it isn't. I suppose, knowing the Admiral, he was bound to try something of the kind sooner or later. We'll just have to hope the experience doesn't drive him back into a catatonic state."

"That could happen?" Crane asked anxiously.

"It would be possible, if he came under too much strain -- that's one reason why I want him to rest. I think he got away with it this time, though. Look, he's coming round now."

"Well, that idea didn't work," Nelson murmured dazedly, opening his eyes and trying to sit up.

"Take it easy," Crane told him. "You've had quite a shock."

"I'm all right," Nelson insisted, "but I shan't try that again in a hurry. At least that one seems to have gone away now." Then he frowned. "Lee, you've been hurt. How did that happen?"

"Me? No, Admiral, I'm fine," Crane said cheerfully.

"There's blood all over your shirt," said Nelson. "With a wound like that I can't understand why you're still on your feet. Doc, why aren't you looking after him?"

"Admiral, there isn't any blood," said Crane patiently. "It's just another hallucination."

"Are you sure?"

"Of course I'm sure. Why wouldn't I be sure about a thing like that?" Nevertheless, Crane glanced down at his chest; the Admiral had sounded so convinced that for a moment he wondered if the almost-healed scratch across his ribs had started bleeding again.

"Oh, very well," Nelson sighed. "I suppose I'll have to take your word for it." All at once, he sounded tired and dispirited.

"Don't worry about it, sir," Crane said encouragingly. "It's bound to take a little time."

"I know," Nelson responded. "Well, you'd better go and get on with your work, Captain."

There was plenty for Crane to do. The waters of the China Sea were crowded with shipping, much of it potentially hostile, and infested with shoals and islands. Navigation there required close attention to charts and equipment, a task almost absorbing enough to keep him from worrying about the Admiral's condition. It was good to return to the work he was trained for, to deal with dials and computer read-outs and men who followed his orders. The morale of the crew, he quickly realized, had been affected by the Admiral's illness; the unspoken thought that he might not recover hung in the air like a thin, poisonous mist. The Captain did his best to damp down the speculation, repeating with forced cheerfulness the official line, that the Admiral was a little shaken by his experiences and needed a few days' rest.

Nelson spent the remainder of the morning, at the Doctor's insistence, resting in bed. He did his best to ignore the apparitions that came and went, only occasionally shooing them away when they came too close for comfort. He felt too weary and battered to try any more confrontations. The business of Crane's bloodstained shirt troubled him; it did not seem to fit the pattern of the other hallucinations. He suspected it might have some connection with his obscure, only half-rationalized, feelings of guilt and failure. The Doctor assured him that such feelings need have no basis in actual events, but with a ten-day blank in his memories Nelson could not quite convince himself that he had not committed some terrible act of betrayal.

In the afternoon, accompanied by a chastened and solicitous Bradley, he went up to sit in the Observation Nose, in front of the windows that looked out on the sea. The journey was something of an ordeal. He knew that he must look ridiculous, swerving to avoid illusory obstacles or picking his way carefully around and over them. Once or twice, leaning heavily on the corpsman's arm, he did manage to walk through the smaller and less threatening illusions, like the river of slime that flowed across one of the corridors. When he found another corridor completely blocked by a wall of flame, however, he had enough trouble preventing himself from calling for a fire detail; he knew that he could not pass through. With commendable patience, Bradley led him back to a junction and took an alternative route. By the time they reached their destination, Nelson had developed a pounding headache and was beginning seriously to doubt the wisdom of the whole venture, but he could not face the return journey without at least a brief rest. Unfortunately, the chair put ready for him was already occupied. He stopped in his tracks, scowling at the blob of purulent green slime that bulged over the edges of the seat; it extended a single, stalked eye and looked back at him.

"Bradley," he said quietly, "would you mind sitting in that chair for a moment?"

"Sir?" Bradley gave him a puzzled look. "Oh, I see," he said after a moment; he was beginning to grow accustomed to the Admiral's foibles. While Nelson watched in tense, horrified fascination, the corpsman walked calmly over and sat down in the chair. The slime-creature oozed around his legs for a few hideous seconds, then gave up and vanished.

"Thank you," said Nelson. "That seems to have done the trick. I wonder why I didn't think of it before?" He sank gratefully into the seat which Bradley vacated for him, and swung it round to face the window. The water outside was a cloudy aquamarine, fading off into sapphire distances; even knowing what he knew -- and few men in the world knew more of the dangers of the sea -- he felt the soothing influence of its beauty. For a long time he was content simply to sit, gazing out into the translucent depths, observing the fish that flashed past, and the diversity of the rock formations on the sea bed.

Later, a few of the crew came, at carefully measured intervals, to speak to him for a minute or two. He felt strong enough, by then, to respond almost normally; he made conventional replies to their polite enquiries, and even smiled once, at a joke from the irrepressible Crewman Kowalski.

"If I hadn't seen the Doctor's report, I'd wonder what all the fuss was about," Morton confided to the Captain after his own brief visit. "Sure, he's a little tired and edgy, but it doesn't seem that bad."

"I just hope he isn't trying too hard." Crane looked up from the chart he was studying. "He is a lot better than he was, but don't let him fool you -- he's still in pretty bad shape. Come and have a look at this chart, will you? Either we aren't where we think we are, or the depth markings are all wrong."

"Oh, that one," said Morton, glancing at it. "It's a copy of an old wartime one -- for some reason the depths are all ten percent out, and even then it isn't too accurate. You remember, we had trouble with it on the way in, but it's the best we have for these waters."

"Oh, yes. I remember. I'll be glad when we get back out into the Pacific." Crane scribbled down a few calculations, and ordered a correction to their course. He had exchanged a few words with the Admiral himself, half an hour earlier, and had not been deceived by Nelson's careful calm. The Admiral still looked desperately tired and unwell, Crane thought, and it was strange to see him sitting so idle, without even pencil and paper to occupy him.

After three hours, Nelson allowed himself to be escorted back to Sick Bay. The trip seemed a little easier, this time; the nightmare shapes lurked in the shadows but did not block his way, and the wall of fire had vanished. Nevertheless, he was tired enough to make no protest when Bradley suggested he try to sleep; indeed, he dropped off almost at once, and slept dreamlessly until dinner-time. When he woke, Bradley had gone off duty, relieved by an older, rather dour man by the name of Carmichael. Almost as soon as he opened his eyes, Nelson knew that it was going to be a bad night. The corners of the room were full of shadows, most of them with eyes that glowed red or green or eldritch blue, and he had not the strength to dismiss them. Courage and logic were of only limited use against such things; in any case, his reserves of both were running very low. The dark water lapped at the fringes of his awareness, and he was deathly afraid of being swept away again, of losing what control he had over his actions and becoming a danger to others.

The meal which Carmichael brought was a nauseating mass of illusory maggots. Short of asking the corpsman to sample the food himself, Nelson tried every trick he knew to dispel the false image: staring hard at the plate; reminding himself firmly that the galley would never allow food to be served in such a condition; looking away and then suddenly back; even trying to take a mouthful with his eyes closed. It was no use. Unable to overcome his revulsion, he finally pushed the food away almost untasted and contented himself with a few sips of coffee. After that, weary and wretched and desperately alone, he lay and watched the monsters as they crept slowly closer. He would not cry out, or try to fight them with physical force: he clung stubbornly to that last shred of sanity until sleep took him.

He was drowning again, choking in cold black water with slimy tentacles dragging him down: far above there was a circle of light that must be the surface, but however hard he struggled he could not reach it. Voices echoed in his ears, unintelligibly muffled and distorted, fading and returning. The distant light wavered, growing dimmer, even more unattainably distant. He was sinking, sinking forever into the dark depths. He made one last, convulsive effort to reach the surface, knowing somehow that if he did not succeed now he would be lost forever.

Then there were strong hands grasping his shoulders, drawing him up into the air and the light, and a voice that carried even through the water. Suddenly his head was above the surface. He drew breath in great shuddering gasps, gradually becoming aware that someone was holding an oxygen mask over his face and that a hand was wiping away the salt water that distorted his sight.

"Easy, sir," Crane said gently. "Easy, now. It was only a dream."

"I was drowning . . ." Nelson croaked at last, when his breathing had steadied.

"I know, sir. But you're safe now. Just try to relax."

"What time is it?" Nelson asked, a little later. He tried to sound casual, but the question was important.

"Just after midnight," the Doctor told him, stifling a yawn. He was in his pyjamas and dressing gown, and looked as if he had been rudely wakened from his first sleep.

That meant another six or seven hours of the night were still to come, Nelson realized with dismay. He did not feel particularly safe, with the shadow-creatures still crowding close, but he knew he should not keep the Captain from his rest.

"Go on, Lee," he said, "it must be long past your bedtime. I appreciate the help, but I'll be all right now."

Crane gave the Admiral's shoulder an encouraging squeeze. "Sleep well, sir," he said quietly.

"Was it really necessary to disturb Captain Crane?" Nelson enquired when he had gone.

"I'm afraid so, Admiral," the Doctor replied, looking troubled. "We had to wake you from that nightmare somehow, and I just couldn't get through to you."

Three hours later, it happened again. It was not drowning, this time, but falling down an endless cliff, bouncing off boulders, snatching at straggling bushes that pulled away in his hands. The dark water waited below: he knew that by the time he hit it, he would have no strength left for swimming. When he came back to himself, he was half-lying on the floor several feet away from the bunk, with Crane leaning over him. He felt bruised all over, and his wounded hand throbbed fiercely.

"That's better," Crane said after a moment, relieved and a little out of breath. "Come on, sir. Let's get you back in bed."

"This is getting ridiculous," Nelson murmured, when they had made him comfortable again. "Perhaps you should tie me up or something."

"There's no need for that," Crane said, so quickly that Nelson suspected the idea had crossed his mind. "Look, Doctor," he added, "perhaps I'd better stay here for a while."

"Perhaps it would be best," the Doctor conceded reluctantly.

"You shouldn't have to do this," Nelson protested, dutifully trying to suppress his feeling of relief at the proposal.

"I'll do whatever I have to to help you fight this thing," Crane said staunchly, settling himself in a chair. "I won't promise to stay awake, but I'll be here if you need me."

"Oh, very well," Nelson sighed, closing his eyes. He was loathe to admit it, but he did feel safer with Crane within call. Twice more before dawn, the nightmares seized him, but each time Crane was able to wake him before the attack became dangerous. At last, Nelson fell into a more restful sleep, from which he finally woke of his own accord, just in time for breakfast.

"Good morning, sir," Crane greeted him cheerfully.

"Morning?" Nelson echoed vaguely. Then, slowly, realizing that the long night was over at last, he began to smile. "Good morning, Captain."

"Admiral! What brings you here?" Crane asked, surprised, turning round from the chart table.

"I couldn't stop him, sir," Bradley said apologetically. He had a hand on his charge's arm, but the Admiral, for once, did not seem to need the support. He had come from the Observation Nose into the Control Room with almost his old decisiveness of movement, only swerving slightly to avoid an empty patch of floor at the foot of the staircase.

"Lee, I'm sorry to interrupt," he said, "but there's something out there."

"What sort of thing?" Crane enquired, putting down his pencil.

"I'm not sure what it is," Nelson replied, "but it's big. It's been around most of the day, coming and going outside the nose window."

"Now, Admiral," Crane said as patiently as he could, "you know that isn't possible. For one thing, nothing could keep up with Seaview for that long, at the speed we're going. For another, if there was anything, it would show up on the sonar."

"I know what you're thinking," said Nelson, "but I don't believe I'm imagining this. I can tell the difference most of the time, you know, and this isn't like the other things. It's too big, and not ugly enough, somehow."

"All right, sir," Crane said resignedly. "Come and look at the instruments." He was a little concerned, but he hoped that the Admiral would be pacified if it could be proved that what he had seen did not exist. He did not like to think of the effect this little scene might be having on the crewmen in the Control Room. As long as the Admiral sat quietly by the big window, it was possible to keep up the pretence that he was convalescent, but if he started drawing attention to his hallucinations in public, the whole crew would soon realize just how ill he really was. Oddly enough, though, Nelson did not appear particularly deranged at present; indeed, he looked more alert and interested in his surroundings than he had since his rescue.

"Should I get the Doctor, sir?" Bradley suggested, relinquishing his hold on the Admiral's arm.

"There's no need for that," Nelson protested, but Crane nodded, overruling him.

"You see, there's nothing there," he said, as they bent together over the sonar screen. "Right, Kowalski?"

"I'm not sure, Skipper." Kowalski frowned over the screen, and pointed out a blurred feature a little off-centre. "Look here. It isn't strong enough for anything solid, but it's big."

"Surely that's just a patch of colder water," said Crane, wishing that Kowalski had had the sense to give him the answer he wanted.

"I thought that too, sir, but it seems to be keeping pace with us."

"How long has it been there?" Nelson was studying the fuzzy patch on the screen with an odd expression on his face -- healthy curiosity conflicting with something like terror.

"Two, three hours, sir, on and off. The range varies a bit, though. Mr Morton didn't think it was anything important."

"I'm sure he was right," Crane said quickly. This unfortunate coincidence was not going to help matters at all. "Nothing solid could make a signal that diffuse."

"It might if it was shielded from sonar in some way," Nelson said thoughtfully.

"But that's impossible!" exclaimed Crane.

"So are a great many things," Nelson pointed out. "That doesn't always stop them being true." He sounded troubled, now, almost as if he would rather not have believed what he was saying.

"Come on, sir. Are you asking me to believe in a creature that's fast enough to keep up with us at standard speed, that doesn't make a proper sonar signal because it has some mysterious cloaking mechanism, and that even you haven't seen clearly enough to know what it is?"

"I'm asking you to prove it doesn't exist," Nelson said quietly. "I know I saw something -- I also know that doesn't prove much either way. I'd like to be sure, one way or another. Please, Lee. At least come and look out the window."

Crane sighed inwardly. "Fine. If I look out the window and don't see anything, will you be convinced?"

"If it's where that signal says it is," Nelson replied, "we may have to turn a little to bring it in view."

"Right." If he was going to humour the Admiral, he might as well do it properly. Crane picked up a microphone and gave the necessary orders. The submarine slowed, first to one-third speed and then to dead slow. "Keep track of that signal," he told Kowalski. "Chip, the Admiral and I are going forward. Give us a minute to get in position, then take us round in a tight circle until I tell you to stop."

"Aye, sir," Morton responded, only a little dubiously.

With Bradley hovering in attendance, Crane escorted the Admiral back to the nose, where the Doctor waited discreetly in the background.

"Now, sir," said Crane, "let's see what's out there." He took his own stand behind Nelson's chair, looking out into the translucent sea, and reached for a microphone. "Tell me when you see it."

"There's nothing there now," Nelson reported.

Behind them, in the Control Room, Morton gave an order. Slowly, the nose of the submarine began to swing in a majestic arc.

"You see, sir? Nothing but water and seaweed," Crane was saying. Then, suddenly, he saw it, no more than four hundred yards away. "What is that?" he gasped. Slender, sinuous, dappled turquoise and ultramarine and all the colours of the sea, it was easily half as long again as the Seaview; a mane of slender spines crowned the huge, horse-like head.

"T'ling Ko'ot," said the Admiral, in a very strange voice. "The Serpent of the Sea." He sat down rather heavily, pressing a hand to his forehead.

"Admiral?" For a moment, Crane thought Nelson was about to faint; he had turned deathly pale, and his eyes were closed. "Is he going into shock again, Doctor?"

"I wouldn't be at all surprised," the Doctor replied tartly. "A thing like that is enough to startle anyone."

"It's all coming back," Nelson said presently, raising his head. "All of it." He shuddered violently. "That -- creature -- out there is part of it. Terrible, terrible things."

"Easy, now," Crane said soothingly. "Whatever happened back there, it's over."

"It isn't over," Nelson contradicted. "It's hardly even started. We might still have a chance to stop it." Briefly, he sounded almost like himself, but his eyes were haunted.

"Where did that come from?" Morton demanded, coming up behind the little group at the window. "How did it get so close? What are we going to do about it?"

"It doesn't seem to be threatening Seaview," Crane said slowly, unable to take his eyes from the creature. There was something terrible, almost unreal, about its beauty.

"Not yet." Nelson's voice was low and troubled again. "It was created to threaten the whole world -- they won't waste it on us unless they have to."

"I'm sorry, sir, but you aren't making any sense," said Crane.

"I suppose I'll have to tell you from the beginning," said Nelson. "But not here. Could we go to my cabin?"

"I don't see why not," the Doctor said, responding to Crane's silent referral of the suggestion to him, "but I'd like to come along, if I may."

"Oh, by all means," Nelson said easily. "Chip, keep the Serpent under observation, but don't do anything to anger it."

"Aye, sir," said Morton automatically, before he remembered that the Admiral was not supposed to be giving orders.

Crane nodded, quietly confirming the order.

"Well, Admiral?" Crane prompted. Looking at Nelson as he sat in the big leather chair behind his desk, he could almost believe that he was completely recovered. Only a slight tremor of the Admiral's left hand, as it gripped the chair arm, hinted at the desperate effort with which he was clinging to the crumbling edge of sanity.

"Kwaishan," he said slowly, as if still struggling to put his thoughts in order. "A poor, backward little dictatorship in the China Sea, with a lousy human rights record but no other claim to fame. But all the major powers have been watching her very carefully -- or trying to. Unfortunately, not many of the agents ever make it back. Their counter-espionage is brutal but very efficient -- so much so that it suggests they have something spectacular to hide. There are plenty of rumours, though. The usual theory was that they were planning to hold the world to ransom with some new kind of weapon, but there was no evidence that they had any kind of nuclear technology. Then, a couple of months ago, one middle-sized warhead went missing from a shipment, and everything pointed to Kwaishan as the place where it went. The espionage was stepped up -- but the CIA had gotten tired of losing agents, and they had picked up a few hints that the mysterious delivery system the Kwaishan government had been working on was some kind of underwater device. That was where we came in.

"I was supposed to investigate the possibility of an underwater missile system, then return to Seaview and take appropriate action to deal with it. To minimize the possibility of leaks, no-one was to know exactly what I was after until I came back aboard.

"My contact was a retired Professor of Marine Biology. He didn't know much himself, but he dropped a few hints, gave me a few names that put me on the right track. I spent a couple of days setting up meetings in seedy cafes, talking to scared laboratory assistants through second-rate interpreters, before I even guessed what was really going on. It seemed so incredible that if any of the agents who'd been through the hands of the secret police ever tried to report it, they'd probably never be taken seriously." Nelson gave a small, wry smile. "Yes, I know. Apart from that thing out there, there's no reason for anyone to believe me either."

"You knew what you were risking?" Crane asked, horrified.

"Oh, I knew," Nelson replied sombrely. "And I have a fair idea what my chances are."

"Every case is different," the Doctor said hastily. "Given the progress you've made in the last few days . . ."

"Well, never mind that now." Nelson dismissed the subject of his own condition with a quick shake of the head. "The serpent-creature is a genetic construct, engineered from a much smaller species of water-snake. The sonar-cloaking is a natural feature of that species -- it's actually not that uncommon in marine life. The thing that makes that creature unique -- quite apart from its sheer size and speed -- is that it has been conditioned to respond to electrically transmitted signals. Within limits, its movements and actions can be controlled by its masters."

"So what do they intend to make it do?" enquired Crane. The story sounded fairly unlikely, but he had heard stranger ones that were indubitably true.

"As far as I could make out, it's supposed to deliver the stolen warhead to its target," Nelson replied. "It may be carrying it now, but I can't be sure of that. Unfortunately, I wasn't able to find out what the target was, but I got a strong impression that they were thinking in terms of world-wide destruction."

"Then why would it be following us around?"

"I don't think it is," Nelson said thoughtfully. "Not deliberately, anyway. It could well just be going the same way for a while -- this is the only clear channel out into the Pacific, after all. On the other hand, there's just a possibility that they have something in mind for the Seaview. I seem to remember they asked me a lot of questions about her speed and crush depth, but all that is rather . . . confused." He paused, rubbing wearily at his temples. "They picked me up at the Professor's house. I arrived for a meeting and found him dead in his study. The place had been ransacked . . . papers strewn everywhere, books thrown off shelves, cabinets jimmied open, and he was lying in the middle of it all, shot through the head. I was looking around, and something hit me from behind. The next thing I knew, I was tied to a contraption like a dentist's chair, in a little room with white tiled walls.

"There were three of them, I think -- two ordinary Secret Police bullies and another one who told them what questions to ask. They didn't waste much time on straightforward questioning: they hardly even bothered with threats. They wanted answers quickly, and they knew how to get them. After about ten minutes they brought out a syringe. It was very strange, after that. Cold, at first, and falling, like a general anaesthetic . . . falling a long way. Then . . . floating in the dark, and the questions, over and over. I don't know how long that lasted -- hours, maybe days. In the end the answers . . . just floated to the surface . . . and there were no more questions, just the darkness and the shapes in it." He shuddered convulsively, leaning back in the chair.

"Don't think about it," Crane advised, going quickly to his side. "That's all behind you now."

"Behind me?" Nelson echoed softly. "If only. . ." His face changed suddenly, and he surged to his feet, almost pushing the chair over, backing away from something that only he could see. Then, before anyone had time to react, he crumpled. Crane caught him before he could fall to the floor, and got him onto the bunk with Bradley's help.

"Low blood sugar, probably," the Doctor muttered, feeling his pulse. "He isn't eating nearly enough, quite apart from anything else. Bradley, order up a mug of cocoa from the galley -- extra sweet."

"Aye, sir."

By the time the cocoa arrived from the galley, the Admiral was stirring and trying to sit up.

"Sorry," he murmured. "That was . . . rather embarrassing. Where were we?"

"You should try eating more," the Doctor said prosaically. "Here -- drink this."

"Cocoa?" Nelson looked suspiciously at the dark, mud-brown liquid, and took a cautious sip.

"It should raise your blood sugar a little," the Doctor explained. "You can't live on thin air indefinitely, you know."

"I do . . . try," Nelson excused himself, between gulps of cocoa. He drained the mug and lay back for a moment. A little colour was coming back into his face, but he still looked deathly tired. "We have to find out where the serpent is going," he said presently. "Whatever they intend to do, it has to be stopped."

"It isn't our problem any more," Crane pointed out. "We're supposed to be taking you home for treatment."

"You know there isn't any treatment," Nelson said wearily. "A day or two isn't going to make much difference."

It was not the days that presented the difficulty, Crane thought, but the nights. He had not the heart to remind the Admiral that he was in no state to undertake a dangerous mission.

"What do you want to do?" he asked instead.

"Just follow it, for the time being," replied Nelson. "If it is carrying the warhead, we can't risk attacking it. If it isn't, we may find out where their base is. There must be one, somewhere out in the Pacific -- they could never have kept a creature like that secret for so long in their home waters."

"I'll talk to Headquarters," Crane offered. "We can patch through some pictures of the serpent to prove it really exists, and tell them what you learned in Kwaishan. Then, they can either order us to deal with it, or make some other arrangements."

"I'd like to talk to them myself," said Nelson.

"I'm sorry, Admiral," Crane said firmly, "but I don't think that would be a very good idea. With respect, the state you're in, they'd take one look and assume you were imagining the whole thing."

"But you don't think that?"

"No, sir," Crane said deliberately. "If I hadn't seen the Serpent for myself, I might -- but the thing's there all right, and any creature that size, with sonar cloaking, has to be worth a little investigation. As for the rest of the story, well, it isn't that far-fetched compared with some things we've run up against. I'm prepared to go along with it, at least for a while, if I can get permission."

"Thank you, Lee. I do realize that this puts you in a difficult position."

"It isn't your fault, sir."

Crane left the Admiral resting on his bunk, under Bradley's watchful eye, and went off to raise Headquarters on the video-phone. He was gone for nearly half an hour. When he returned, Nelson was sitting up again, looking as though he would rather have been pacing the floor. The monitor screen on the wall showed the view from the nose camera; the great serpent was still well within visual range, gliding purposefully through the water.

"Well?" Nelson asked eagerly.

"We've got the job," Crane told him cheerfully. "After all, we're ideally placed for it. We're supposed to keep following the creature and report developments, but I've been given full discretion in case of emergencies. Oh, and they're glad to hear you're feeling better, sir, but I'm not to let you over-exert yourself."

"That's kind of them," Nelson commented. "I take it that means I'm not in command of this operation?"

"You know you aren't fit for that yet, sir. I'm always open to suggestions, though."

"That's fair enough, I suppose," Nelson conceded. He frowned, and one hand twitched as if he wanted to strike out at something.

"You'd better try to get some rest," said Crane, recognizing the signs. "I'll let you know if anything interesting happens."

The serpent moved swiftly, heading out into the Pacific on an unnaturally straight course. By the time darkness fell, the crew in Seaview's Control Room had learned to recognize the faint, elusive signal on their sonar screens, and the pursuit continued unhindered.

Nelson stayed in his cabin, pondering his recovered memories and trying to ignore the monsters, until dinner-time. Then, to Bradley's surprise, he asked to be escorted to the Officers' Mess. The corpsman tried to dissuade him, but finally agreed to ask the Doctor's permission, which was rather reluctantly granted.

The Admiral's appearance at table, a couple of minutes late and leaning heavily on Bradley's arm, caused a sudden lull in the conversation. Forcing himself not to flinch from the gaze of so many eyes, he let the corpsman help him to his usual place. His reasons for this experiment were complicated. In the first place, he hoped that, seeing others eat, he would be better able to convince himself that the food was indeed edible. There was also something -- if only a dim personal satisfaction -- to be gained from proving to his colleagues, and even to himself, that he could still behave normally. The third, most secret and shameful, reason was that he was in no hurry to return to Sick Bay, to the custody of the unsympathetic Carmichael and the prospect of another night of terror. So, he sat among familiar, friendly faces, doing his best to join in the conversation, eating what little he could manage, and keeping up the pretence of being almost recovered. He tried not to watch the blood that ran steadily down Crane's shirt-front to make a sticky, spreading pool on the table, or the clouds of noiseless flies hovering over every plate, but from time to time he would realize that he had not heard a word that was said to him for several minutes.

The meal ended at last, and the night was still to be faced. He thanked Bradley, who was going off duty, and responded politely to the cheerful good-nights of the crew, and let Carmichael lead him away.

The corridors were full of thin, liquid darkness, transparent as ink-stained water, breathable as air. He floated swiftly along the well-known ways, darting fish-like out of reach of the pursuing shadows, heading for the open water where he might at last be free of them.

"Skipper! Wake up, sir!"

"What?" Crane murmured drowsily. "All right, Patterson, you can stop shaking me now."

"Sorry, sir. I couldn't wake you any other way."

"What's happening?" Crane sat up, trying to force his eyes open against the pressure of the light, realizing that he must have fallen asleep without even undressing.

"It's the Admiral, sir. We can't find him."

"What?" Crane sprang to his feet, as thoroughly roused as if the crewman had flung a bucket of cold water over him. "How did that happen?"

"He was sleeping, sir, and the corpsman just went out of the room for a couple of minutes. When he came back, the Admiral was gone."

"How long ago was this?" Crane demanded.

"No more than five minutes, sir. The corpsman called the Doctor first, and he said to let you know."

"Right. Thanks, Patterson." With a cold dread in the pit of his stomach, Crane reached for the intercom. "Attention all hands, this is the Captain. Admiral Nelson has left Sick Bay. He must be found and returned there as soon as possible. Be careful -- the Admiral may not be in his right mind and he could be dangerous. Repeat -- he may be dangerous."

"He isn't in his quarters, or the Observation Nose," the Doctor reported, putting his head round the cabin door. "Have you any ideas, Captain?"

"How should I know?" Crane asked rhetorically. "Even when he's in his right mind, I can't always predict what he'll do next! He can't have got far -- he certainly can't get off the ship." He thought frantically for a moment. There were so many kinds of death lying in wait among the labyrinthine corridors of the submarine. "The Armoury? No, there'd be someone there. The Missile Room? Surely he wouldn't start firing torpedoes at his monsters?" Then he stopped short. "The Missile Room! The escape hatch! Come on, we have to stop him." He gave a few quick orders over the intercom, then set off at a run, with Patterson and the Doctor trailing in his wake.

The corridor outside the Missile Room was empty, but the watertight door was open. Crane sprang through, just in time to hear the gurgle as the water-level indicator on the escape hatch began to rise. He sprinted across the floor, dodging around the torpedo racks, and pressed the buttons to abort the flooding of the chamber. The water level was already more than six feet. Grimly, Crane waited while the chamber drained, then spun the wheel of the locking mechanism and wrenched open the door. Nelson lay in a drenched huddle on the floor of the chamber. He was not breathing, but there was a faint pulse at his throat.

"Come on," Crane heard himself muttering, as he applied first-aid. "Come on, Admiral. Don't give up on us now -- we need you. Breathe, will you?"

"That's enough, Captain," the Doctor said at last.

"Enough? No, I can't let him die!" Crane gasped, looking up for a moment. There seemed to be a great many people in the room, but he and the Admiral were at the centre of a ten-foot circle of clear floor.

"He isn't going to die," the Doctor assured him. "Look, he's breathing on his own now."

It was true. Nelson was still unconscious, but his chest rose and fell steadily, and his pulse was stronger. Crane rose shakily to his feet and let the Doctor take over.

"It was a close thing," the Doctor said later, "but he'll be all right now -- at least physically. As for his mind, we'll have wait and see."

"Where's the corpsman who left him alone?"

"Carmichael? I sent him to his quarters -- I thought you might like to deal with him yourself, Captain."

"You better believe I would," Crane responded grimly, "but he can stew for a bit longer. I'll speak to him in the morning." He was angry enough to have the unfortunate man scrubbing decks for a week, but some small part of his mind insisted that discipline should wait until he was calmer. "I should have been here," he added, "but he seemed so much better today."

"You need your sleep too," the Doctor said severely. "You can't go on indefinitely like this."

"A few broken nights won't kill me. But how much longer is this likely to go on, Doc?"

"I don't know," the Doctor admitted wearily. "The drug is still in his blood-stream at much the same level it was two days ago. He's fighting it pretty hard, but the odds are against him. We could easily have lost him tonight, and there's no way of knowing that it won't happen again."

Crane sighed. Propped up on pillows to help his breathing, wrapped in layers of blankets, and still unconscious or deeply asleep, Nelson seemed alarmingly fragile. It was hard to believe that only that afternoon he had been sitting at his desk looking almost normal.

"From now on, I want two people with him at night," he said, "and Carmichael is not to be one of them. It may not be his fault, but he doesn't seem to be a lot of use."

"Very well, Captain. I'll see to it."

"And I'm not leaving, at least until he comes round," Crane added, a little defiantly. "Is there any chance of some strong coffee?"

"I think that could be arranged. I must admit, I could use some myself."

The depths were warm, peaceful, empty of shadow-creatures; he could have drifted there for ever and been content. Slowly, though, he became aware of the pained rasp of his own breathing, and of low voices somewhere near, and then of a hundred small, nagging discomforts, stinging abrasions and throbbing bruises that would not let him rest any longer. He stirred fretfully, knowing that he would have to go back and face the monsters again.

"Admiral? Can you hear me now?"

"Of course I can hear you, Lee," Nelson said testily, opening his eyes. His throat was raw, and there was a taste of oily salt water in his mouth; the effort of speaking brought on a spasm of coughing. "I'm quite capable of waking up on my own," he added when he could catch his breath again. "I wish you'd go and get some sleep before you bleed to death completely."

Crane shook his head as if he did not know whether to laugh or cry. "What are we going to do with you?"

"What are you talking about? I had a dream, that's all -- not even a very bad one, by recent standards."

"I'm afraid that isn't quite all, Admiral," the Doctor said gravely. "You went walking in your sleep."

"Only walking? All right, you'd better tell me all of it."

"What's going on, Chief?"

"What do you mean, going on, Kowalski?"

"Oh, you know. First we're on a secret operation, then the Admiral gets sick and we're going home. Now we're chasing this sea-serpent thing, but the Admiral isn't any better, and the Skipper's walking round looking like he hasn't slept for a week. And that business last night -- what was that all about?"

"Nothing you need to worry about, Ski," Sharkey said cheerfully. "Okay, the Admiral isn't too well, but he's going to be fine. All we have to do is carry out orders -- starting with this engine. It hasn't been right since that typhoon, and we have to figure out why."

"Did you see the Admiral this morning?" Kowalski demanded, unconvinced. "Sitting up there by the window, with that corpsman watching him all the time, like he might go crazy any moment -- if he isn't already. He doesn't even seem to be in the same world as the rest of us most of the time."

"That's enough," Sharkey told him sharply. "The Admiral's been going through a pretty bad time, but he is not crazy, do you hear?"

"Whatever you say, Chief."

"Not too good," the Captain said bluntly, when Sharkey asked him about the Admiral's progress a few hours later. "Not as bad as he was back on shore, but bad enough. That business last night hit him pretty hard. I thought at first it was going to be all right, but after a while he went very quiet, and he's hardly spoken since."

"He will get over it, won't he?" Sharkey asked anxiously.

"I certainly hope so. The Doctor says we just have to be patient with him for a while."

Sharkey shuffled uncomfortably.

"Carry on, Chief. Or was there something else?"

"Skipper . . . if there's anything I can do to help, you will let me know?"

"Of course, Chief." The Captain fidgeted with his signet ring for a moment, and then ran a hand over his hair, rubbing the back of his neck. "Right now, though, I'm not sure there's much that any of us can do except wait and get on with our jobs."

"You know, Lee, this stuff isn't bad." Nelson set down a half-empty mug of soup, and managed a tentative smile.

"Oh, you're back again, are you?" Unconcealed relief brightened Crane's face.

"Back?" Nelson echoed vaguely. "I suppose so. How long has it been?" He remembered, dimly, a time when dreams and hallucinations blended into one endless, inescapable torment, so that simply to keep from screaming took all the strength he had. He had found his way back, somehow, groping along a fragile chain of rationalizations, helped by the patient reassurances of those who cared for him, but in the process he had lost track of time.

"Well, we've hardly had a word out of you since the night before last -- going on for thirty hours." Crane was smiling, but the strain of too many almost sleepless nights had set its mark on him; there were lines in his face that had not been visible before, and shadows as deep as bruises under his eyes.

"As long as that? I was trying to think, but I got lost somewhere. Madness and dreams and death . . ." Nelson shook his head, and reached for the cup again, trying to gather his thoughts. "Where's Bradley?" he asked after a moment.

"Not far away. Do you want him?"

"No. I just wondered why you were here all of a sudden. Haven't you got a ship to run?"

"I relieved Bradley for a few minutes. There's not much happening, anyway."

"I can see that." Nelson swung round to look at the quiet, orderly Control Room behind them. A slow, viscid trickle of blood ran down the computer's wall of blinking lights, and something large and hairy skulked under the spiral staircase, but he was growing almost used to such manifestations. He turned back to the window. The Serpent was still in sight, a deeper blue shadow in the dimness of the water. "I hope I haven't been giving you too much trouble," he said quietly.

"Well, apart from having to be waited on hand and foot, and watched all night, not really," Crane told him, in a gently teasing tone. "We made sure you didn't do any more sleep-walking."

"So," Nelson asked after a pause, "what's been happening?"

Crane gave him a measuring look. "Finish your soup before it gets cold," he said carefully, "and I'll tell you about it."

Nelson quirked an eyebrow and obediently swallowed a couple of mouthfuls.

"We've been following the Serpent pretty closely," said Crane, satisfied. "It sets a good pace, but nothing we can't match. I took the Flying Sub out yesterday for a closer look, and got some interesting film. There's no sign that it's carrying anything, but there's definitely something odd about the way it behaves. I got within less than twenty feet of it, and it hardly seemed to know the Flying Sub was there -- it just kept going straight ahead."

"That's only to be expected, if it's being controlled by something other than its natural instincts," Nelson commented. "Did anyone think to try picking up the control signal?"

"Sparks did pick up something. We can't make head or tail of it, but it does seem to change just before the creature turns."

"What about the course?"

"Now that's another interesting thing. It looks like someone marked it out with a ruler -- dead straight for a hundred miles, sometimes, and then a sharp turn. We nearly lost it once when it took a ninety-degree bend in the middle of the night."

"I'd like to see it plotted, if I may."

"Since when did you need permission to look at charts in your own Control Room, sir? If you can manage a few steps, I'll show you."

"Of course I can walk. I may need a little help, but I can manage." Nelson rose, only a little unsteadily, and took Crane's proffered arm more because he was out of the habit of walking unaided than because he needed the support. For once, the floor remained solid, unencumbered by illusions. Grateful for the respite, he refused to worry about how long it would last.

"We've been marking it up every quarter-hour," Crane explained, pointing out the series of pencilled crosses on the chart, each with a date and time indicated.

"Fascinating," Nelson leaned over the table for a closer look, absently brushing away a small, many-legged creature that crouched in the centre of the chart. "You see what all these sharp turns are for, of course?"

"It seems to be avoiding inhabited islands and the main shipping lanes."

"Exactly. Apart from those detours, I'd say it was headed . . . this way." Nelson ran a finger over the chart, indicating a line that slanted south-eastwards across the Pacific. "Now why, in all the seven seas, would they want to go there?" he wondered.

"There's nothing much along that way until the coast of South America," said Crane, puzzled.

"Not much land," Nelson corrected. "There is some very deep water, though -- ocean trenches so deep they've never been properly charted or explored." He was reaching to point out the area when the floor suddenly tilted under him, flinging him away across the room. Waves of darkness crashed soundlessly about him; it took him a few seconds to realize that the submarine really was rocking in the water, sending everyone staggering from one side to the other.

"Engineering!" barked Crane, clinging to the rail of the periscope platform with one hand and clutching a microphone in the other. "What's happening? Can you stabilize?"

"We just lost the starboard engine, sir," came the reply after a moment.

"All stop," Crane ordered. "Level off."

The rocking motion ceased abruptly, but the floor remained canted at a dangerous angle: the submarine had gone into a steep dive.

"Level off!" Crane repeated. "Close crash doors," he added. "Rig for collision." The foot-thick metal doors separating the Observation Nose from the Control Room slid silently into place. "Bradley, get the Admiral out of here!"

Nelson crouched in the corner where he had been thrown, clinging to a chair-leg. Lights glared through the shadows, flickering like flames; blood gushed from a pipe overhead and made a spreading pool over the deck. Shaking his head, he closed his eyes and forced himself to listen to the voices.

"Control, this is Engineering. There's no way we can pull out of this dive!"

"All right, Chief. Pull up as far as you can and brace for collision!"

The room lurched again, tearing Nelson loose from his hold on the chair-leg, then flinging him back to the deck. We've hit bottom, that's all, he told himself, bracing for the inevitable aftershocks as the hull bounced on the seabed.

"Damage Control! Report!" That was Crane, out of breath and muffled, as if he was picking himself up from the deck.

"All sections tight and dry, sir, but the starboard engine's out of commission and there's something wrong with the reactor. With the emergency generator, we've got air for about four hours."

"Can you make repairs?"

"It's going to take a while, Skipper."

"How long?"

"I'm not sure, sir."

"Get on with it as fast as you can. I'll come down and take a look." There was a click as Crane stowed the microphone. When he spoke again, there was a note of exasperation in his voice. "Bradley, I thought I ordered you to get the Admiral out of harm's way."

"I'm sorry, sir. I can't get him to move." That was Bradley, quite close and sounding unhappy.

"Keep trying," Crane said curtly.

"Come on, sir," Bradley coaxed. "I have to take you to your quarters for a while."

"No," said Nelson. "No." The first time he sounded like a peevish child, but with the second he raised his head, and managed to put some firmness into his voice. The Control Room was knee-deep in black water, with blue and green flames dancing over the scummy surface and shapeless bundles that might be corpses floating here and there. He let Bradley help him to his feet, and stood for a little while, leaning on the corpsman and fighting to see beyond the hallucinations. The reality was not quite so bad: chairs had been thrown about; one or two instrument panels were smashed and smoking; but no-one appeared to be hurt.

"Come on, sir," Bradley said again.

"No," Nelson repeated. "We have to go to the Reactor Room." Even at the thought, a wall of flame sprang up all around him.

"The Reactor Room?" Bradley echoed, horrified. "Sir, you can't!"

"I certainly can't do it on my own," Nelson agreed. "Now, are you going to help me or do I have to find someone else?"

"Why do you want to go there, sir?" asked Bradley, weakening.

"We're going to save the ship," the Admiral replied simply. "Are you coming?"

"I'm coming, Admiral."

"Bradley, what do you think you're playing at?" Morton demanded, coming over to the pair in time to catch this last exchange.

"Leave him alone, Chip," Nelson said wearily. "He's following my orders."

"Admiral, you're in no condition to be giving orders. If you won't go to your quarters I'll have to have you sedated."

"I know what I'm doing," Nelson met the Executive Officer's harassed frown with the most direct and authoritative look he could muster. "We both have better things to do than argue about it." He was not at all sure that he could hold on to his reason for long enough to do what needed to be done; he certainly had neither the time nor the energy to debate the matter. "Now get on with your work," he added crisply.

"Aye, sir," Morton responded almost automatically to the tone of command.

"Right," said Nelson. "Let's go, Bradley."

It was not an easy walk. The tilted corridors were full of men hurrying about their work. The crash had started several small fires, mostly extinguished now but still filling the air with fumes and smoke. Without Bradley's guidance, Nelson would have had difficulty distinguishing the real hazards from the illusory ones; try as he might, he could not see through the swirling black water to the floor he trod on, and though he knew that some of the hurrying figures were not real, he could not be sure which they were. He clung to the corpsman's arm and went where he was led, sometimes closing his eyes for a few steps. It would have been quite easy, he realized, for Bradley to take him back to his quarters after all; the familiar passages had become so terrifyingly strange that he had no clear idea where he was.

"It looks like something broke loose inside the turbine and got forced back into the steam pipe from the reactor," Sharkey explained, wiping his hands on a greasy rag. "There's been a fault on that engine since the typhoon, but we couldn't track it down. It went with an almighty bang -- there could be a lot of damage inside."

"Can you clear the blockage?" Crane asked, frowning at the crippled engine.

"Not without shutting down the reactor and stripping out the whole system, Skipper," Sharkey replied bluntly.

"How long would that take?"

"Normally, we'd do it in dry dock and take a couple of days over it. We haven't got a couple of days, have we, sir?"

"A couple of hours, maybe," Crane said grimly. "Can we run on the other engine?"

"Negative, sir. The reactor's already heading for critical mass -- we have to shut it down."

"This doesn't sound too good," Crane remarked. "All right, Chief: we'd better have a look at the reactor."

The situation in the Reactor Room certainly appeared ominous. Warning lights flashed in an erratic, accelerating rhythm, counterpointing the pulsing, actinic light from the reactor itself.

"The controls are jammed, sir," Kowalski reported breathlessly. "I can't shut it down."

"Get out of the way," Crane ordered. "Let me try." He tried a few switches, then shook his head. "It's no good."

"How long have we got, Skipper?" Sharkey asked tensely.

"Less than an hour, by the looks of it," replied Crane. "That fragment of turbine must have lodged somewhere vital. Unless we can shut down, the reactor's going to blow and take the whole ship with it."

"Then we'll have to find a way to shut down," put in a familiar and unexpected voice.

"Admiral! What are you doing here?" Crane swung round in surprise.

"Don't you start," Nelson said tiredly. "I came because I might be able to help."

Crane took a deep breath, holding back the retort that sprang to his lips. At first glance, the Admiral, leaning heavily on Bradley, did not look in any condition to tackle a runaway nuclear reactor. There was a grim determination in his face, however, in spite of the haunted, half-blind look of his eyes: for the time being at least, he was hanging on to some measure of sanity. Whatever his condition, he undoubtedly knew the reactor better than anyone else.

"We're in trouble, sir," Crane said bluntly. "If you have any ideas, I'd be glad to hear them."

"Give me a chance to look at it." Nelson moved over to study the control panel, frowning with concentration. He reached out as if to wipe some sticky substance away from the dials and switches, then shook his head. "Bradley," he said quietly, "I can't see well enough for this -- you'll have to read the dials for me. Just read each one out as I point to it."

Bradley looked puzzled, but obeyed. When they had gone over the dials, they repeated the process with the banks of indicator lights.

"That's where the trouble is," Nelson said at last, tapping at one cluster of lights on the panel. "The fragment from the turbine blocked the vent pipe from the reactor -- the pressure's building up and blocking the control mechanism."

"So what do we do?" enquired Crane.

For a moment, Nelson looked lost, helpless, and desperately weary.

He can't do this, Crane thought. He shouldn't even be here. We're going to have to do this ourselves.

"There is a way," Nelson said, slowly, as if he was groping in the dark after memories of how things ought to look. "If we put in a new length of pipe to by-pass the blockage, the pressure should fall enough to let us close down the reactor and make proper repairs. It'll be close, though -- there's only just enough time."

"Then we'd better get on with it," Crane said briskly. "Where is this blockage?"

Nelson leaned on the edge of the control panel, squeezing his eyes shut, deadly pale and swaying on his feet.


"Just give me a moment," Nelson murmured.

He's going to pass out again. I've got to get him out of here. Crane was on the point of giving Bradley an order to that effect when the Admiral took a shuddering breath and straightened up.

He frowned at the control panel and shook his head. "It should be behind the third access door on the left."

"I've got it, sir." Sharkey levered open the door to reveal a tangle of pipework and valves and wires.

"Right." Clinging rather desperately to the patient Bradley's arm, Nelson came over to look. "There," he said after a moment, pointing out one particular section of pipe.

"Are you sure?" Crane peered dubiously at the exposed innards of the submarine. There was an enormous risk in accepting such specific instructions from a man whose grasp of reality was tenuous at best.

"Of course I'm sure," Nelson said impatiently. "You can check the plans if you like, but I tell you that's the place." His face twisted into an expression of disgust, and he pulled his hand back from the pipe, wiping it against his trousers.

"I think the Admiral's right, Skipper," said Sharkey. "The temperature's much higher at the reactor end of the section."

"All right, Chief. Can you by-pass it?"

"I think so, sir. You see there's a valve here, and another one here -- it shouldn't be too hard to bridge a piece of pipe between them."

"Will this piece do?" Kowalski had spent the past few minutes rummaging in a spares cupboard, and now produced a two-foot length of heavy-gauge six-inch diameter stainless steel tubing.

"That looks about right," Nelson pronounced. "Now, we'll need joints, welding equipment . . . "

The repair took nearly half an hour. Nelson supervised the whole operation, monitoring the temperature and pressure readouts with Bradley's help and offering occasional suggestions and warnings. Crane, satisfied that he knew what he was doing, did not interfere, but he stayed in the Reactor Room. He could see all too clearly the price that the Admiral was paying for his stubborn refusal to relinquish responsibility; it was quite possible that he would lose his fragile hold on reason before the task was complete. At the least, Crane thought grimly, they could be in for a very bad night.

It was done at last, and the pressure in the reactor fell rapidly as the trapped steam escaped along the replacement section of pipe. After a few minutes, the jammed mechanism released, so that it was possible to shut down the reactor.

"How long before we can get under way?" Nelson asked then.

Crane looked sideways at him, wondering what was on his mind. By rights he should have been in a state of collapse, but it seemed his strength would hold out for a little longer yet; there was something intent and urgent in his voice.

"Well, Admiral, I reckon we can be off the bottom in an hour or so," said Sharkey, "but it'll take longer than that to fix the engine so we can make any kind of speed."

"Too long," Nelson muttered. "We have to catch up with the Serpent."

"Now, Admiral," Crane remonstrated, "suppose we worry about one thing at a time?"

"Next you'll be telling me it's time I had a rest," Nelson retorted.

"You took the words right out of my mouth, sir."

"If we let that creature get too far ahead, we'll never find it again -- and we lose any chance of stopping whatever it's going to do."

"So what do you suggest, Admiral?" Crane asked, resigned.

"You want to do what?" Morton enquired, shocked.

"I want to take the Flying Sub out to follow the Serpent," Crane repeated patiently. "Have you any objection?"

"Of course not, sir -- but taking the Admiral along! Are you sure that's a good idea? I mean, it was bad enough letting him play around with the reactor . . ."

"Before you start questioning my judgement," Crane said in a dangerous voice, "you might remember that without the Admiral's 'playing' there'd probably be nothing left of us by now but a cloud of nuclear fall-out. He could easily have fallen apart under the strain -- but he didn't. If he feels up to carrying on with the mission, I'm prepared to back him up."

"It's your decision, sir," Morton said stiffly, "but I want it understood that I don't agree."

"Put it in writing if you like," said Crane, "but we're going as soon as Seaview lifts off the bottom."

"Very good, sir," Morton said after a brief pause.

"Cheer up," Crane told him. "I haven't gone completely crazy -- it's not as if I meant to let him take the controls. We'll take Kowalski as back-up pilot, and Bradley to look after the Admiral. Yes, I know," he added in response to Morton's sceptical look. "He can't really control the Admiral, but he has his uses. You should have seen the two of them reading the control panel in the Reactor Room."

"Well, there it is, Admiral," said Crane, "right where we calculated it should be."

"Good." It could not be said that Nelson relaxed -- except in drugged sleep, he had not truly relaxed since the interrogation in Kwaishan -- but there was a certain satisfaction in his tone. "Now," he added, "the sooner we can get that homing beacon implanted, the sooner we can get back."

"Well, we can't fire it from the air," said Crane. The Serpent was no more than a wavering, sinuous shadow under the surface of the water, an impossible target to hit with any accuracy. "Hold on everyone -- we're going down." He made a brief radio contact with the Seaview, which was still limping along on a single engine some eighty miles behind, then swung the Flying Sub in a tight curve, a little away from the Serpent's path. The creature seemed indifferent to activity around it, but there was no point in taking unnecessary risks. So far, the excursion had gone without a hitch. The Admiral, strapped into the rear passenger seat with Bradley at his side, looked tired and strained but still well in command of himself.

"Missile ready for firing, sir," Kowalski reported, as the Flying Sub sliced into the water.

"Hold your fire until we get a little closer," Crane ordered. "We can't afford to miss with this one."

"I'd sure hate for it to be wasted, sir," Kowalski said with a grin. He had spent an hour assembling the device, a simple radio-beacon attached to one of the Flying Sub's small missiles: there had been no time to make a spare.

"I hadn't realized how big that thing is," Bradley remarked, as they approached the Serpent. Its head alone was nearly as long as their small vessel, though not as broad; the eyes, round and unblinking, were more than a foot in diameter.

"Aim somewhere near the tail," Nelson advised. "We don't want to do the creature any serious harm at this stage."

"This is close enough," Crane said tensely. He matched the Flying Sub's speed so precisely to that of the Serpent that Kowalski effectively had a stationary target. "Ready -- aim -- fire!"

The missile hit the Serpent squarely, and lodged in the scales just below its spiny backbone, thirty feet from the tail-tip. The creature seemed hardly aware of the impact.

"Good shooting," Crane commented. "Let's get back to Seaview."

"Hold on," said Nelson. "There's something happening. Listen to the control signal."

"It sounds like a course change," said Crane, after a few moments' attention to the irregular bleeping. "It's just as well we caught up when we did."

"There's something odd about it, Skipper." Kowalski flicked switches to get a visual analysis of the signal. "As if . . . as if suddenly there were two signals on the same frequency -- and the second one is much stronger."

"That's what I thought," said Nelson. "Look how the Serpent's reacting."

"We'd better get out of here," Crane said hastily. The creature's steady, purposeful movement had changed; its head swung this way and that as if searching for something, and its whole body writhed in the water. One random blow from that enormous tail could easily cripple the Flying Sub, if not crush its sturdy hull. Crane pulled the craft rapidly out of harm's way.

"It's taking a new course," Kowalski said presently.

"Almost back where it came from," Nelson added. "That doesn't make any sense -- unless the new signal is being sent by someone who doesn't want it to do what it's supposed to do."

"But who?" Crane wondered. "It can't be our side -- they'd have let us know, at least."

"I don't know," said Nelson, "but I think we should find out, don't you?"

Crane hesitated. "Admiral, I need to get you back to Seaview."

"There isn't time," argued Nelson. "By the time you'd gone there and back, whatever is going to happen could already be over. We have to stay with the Serpent."

"If you're sure you feel up to it," Crane said, reluctantly conceding the point.

"I can manage," Nelson assured him.

Crane nodded, and activated his radio. "FS-1 to Seaview. Come in, please."

"FS-1, this is Seaview -- Morton here. Go ahead, Skipper."

"Mr. Morton, there's been a slight change of plan -- we're going after the Serpent."

"You know about the new signal on the Serpent's control frequency, sir?"

"We picked it up just a few minutes ago, just before the creature went charging off in a different direction. We're going to investigate a little further."

"Skipper -- that signal. It seems to be coming from a ship of some kind, only about twenty miles from here. We've been trying to contact them, but they don't respond."

"Do you have co-ordinates?"

"Negative, Skipper. We're still trying."

"All right. Let us know if there are any developments. Over and out."

Once it had begun to follow the new signal, the Serpent moved as swiftly and surely as ever, but the course itself was erratic, with frequent sharp turns, as if the senders of the signal were inexpert at their controls. Crane kept the Flying Sub far enough back to be out of danger even if the creature turned suddenly back on itself.

"They don't know what they're doing," Nelson muttered. "Either that or they're fighting over the controls."

"Seaview to FS-1. Come in, please."

"FS-1 to Seaview. We read you -- go ahead, Chip."

"We got a fix on those signals, sir," Morton informed him. "They're coming from a Soviet trawler -- probably the same one that was hanging about off the coast of Kwaishan."

"Then we definitely need to know why," said Crane. "Get on to the Pentagon and get them to talk to the Kremlin. Whatever they think they're doing, they aren't doing it very well, and that ship could be in big trouble. Did you contact the ship?"

"Very briefly -- they identified, then jammed us out."

"Skipper," Kowalski broke in suddenly, 'something's happening. It looks like the Serpent's heading for the surface."

"Stand by," Crane said quickly into his microphone. Kowalski was right; the Serpent's long body had angled sharply upwards, and its head was already invisible on the other side of the air-water interface. "We'd better surface ourselves and see what's happening."

"There's a ship up there," Kowalski added. "The Serpent's going straight for it. Should we try to stop it?"

"We can't," said Crane, seeing the shadow of the hull no more than half a mile away. "The ship's too near -- we couldn't get the Serpent without sinking the ship too."

The Flying Sub broke surface just in time for its occupants to see what happened next. The Serpent reared out of the water, a hundred-foot tower of scales and spines, dappled with the colours of the sea, scattering spray from its mane, dwarfing the rust-red trawler and its array of radio antennae. Then it came down, slow and majestic and inevitable as a toppling tree or a breaking wave. The ship disintegrated under the impact, in an explosion of smoke and spray and flying, twisted metal. After a moment, the Serpent's great head emerged again, twisting this way and that among the scattered wreckage, darting down to pick up a few choice morsels. Then the creature dived and disappeared.

"Survivors," Nelson gasped, breaking the silence. "We have to look for survivors."

"No-one would have stood a chance," said Crane. "The poor, stupid . . ." He shook his head, trying to look away from the patch of disturbed water where the ship had been less than a minute before. "It all happened so fast," he murmured.

"We have to try," Nelson insisted. "We have to try . . ." His hands were clenched on the safety harness, white-knuckled and trembling, and his eyes were shut.

"Of course, Admiral," said Crane. "We'll do everything we can." He was not sure that Nelson heard him, though he spoke as calmly and clearly as he could. "Take the controls," he ordered Kowalski, swinging round and unstrapping himself from his seat. "Start searching the area." Bradley was already doing what he could, talking quietly and soothingly to his patient while he searched through a case of supplies, but his words appeared to have little effect. After a while, though, Nelson raised his head.

"Here," Crane said quietly, "try to drink some of this."

"What is it this time?" Nelson asked warily.

"Cocoa," Crane said cheerfully. "I'm afraid it doesn't travel too well, but it's still hot. Come on -- try it." He held out the half-full cup of a thermos flask, careful not to spill it as the craft skimmed over the waves. He was not too surprised at the Admiral's reluctance; they had tried a variety of strange concoctions over the last couple of days, in an attempt to get some nourishment into him, and not all of them had been palatable.

Nelson's hands were none too steady, but he managed to hold the cup and swallow a few mouthfuls.

"Is there anything out there?" he asked presently, sounding rather more like himself.

"Only a few bits of flotsam, sir," replied Kowalski.

"Keep trying," Nelson told him firmly.

"Aye, sir." Kowalski put the Flying Sub into another turn. After a minute or so, satisfied with the Admiral's condition, Crane returned to his seat to help with the search.

"Well, will you look at that!" Kowalski said suddenly.

Crane held up a silencing hand: he did not want Nelson disturbed by false hopes. Following Kowalski's gaze, he saw something on the surface -- a lifeboat, capsized but still afloat, and a figure clinging to it, too far gone to react to the presence of the Flying Sub, but just possibly alive.

"Take us down for a closer look," he ordered. "Carefully -- we don't want to swamp him."

The Flying Sub skimmed in a wide, descending curve, touched down with the smallest possible splash, and came to a stop floating a few yards from the overturned lifeboat. Even in the minute or so that the manoeuvre took, the clinging figure had slipped noticeably lower, but he was still there, and -- as they discovered when they brought him aboard -- still alive.

"He doesn't seem to be badly hurt," Bradley reported after a brief examination.

"He must have been thrown clear when the ship broke up," Crane suggested, shaking his head in wonder. It seemed impossible that anyone could have survived such an impact -- yet here the man was, huddled in a cocoon of blankets on the deck and already beginning to show signs of returning consciousness. "I wonder if he speaks any English?"

"Oh, I expect so," said Nelson, with an unexpected touch of humour. "After all, even aliens from the other side of the galaxy seem to be able to manage that -- and he doesn't look much like an ignorant fisherman to me." It was true; though the Russian's clothes were a reasonable imitation of coarse sailor's garb, his hands were slender, free from callouses, and there was a strong suggestion of military discipline in the cut of his blond hair.

They spent another twenty minutes searching the area, but there were no more survivors and little even in the way of wreckage. No-one protested when Crane decided to call off the search and return to the Seaview. The Serpent, still carrying the radio-beacon, was evidently returning to its original course; there was nothing to be gained by pursuing it further at present.

"So this is the Seaview," said the Russian, looking around the Control Room with lively interest. "You are to be envied, Captain."

"She is rather special," Crane admitted. Despite the rivalry between their nations that went back to a time when they had both been children, he found himself rather liking Dmitri Alexandrovich Kirienko. Released from Sick Bay after a couple of hours' recuperation, and dressed in borrowed civilian clothes that did not fit him particularly well, the sole survivor of the lost trawler was a tall, loose-limbed man in his thirties. He had an interesting face, fine-boned and long-nosed, etched already into a network of lines by constant exposure to the elements, with very keen and intelligent eyes of an unusually deep blue. He spoke English very well, with only a trace of Russian flatness in his accent.

"But where is the famous Admiral Nelson?" Kirienko enquired.

"I'll introduce you to the Admiral presently," Crane promised. "I'd better warn you, though -- you may find him a little . . . different from what you expected. He hasn't been too well lately."

"Oh?" Kirienko's tone was one of polite concern, but his look was suddenly, disconcertingly shrewd. "I hope it is nothing too serious?"

Is it so obvious that there's something wrong? Crane thought wearily. He resisted a powerful urge to confide in this stranger. "It isn't bad enough to stop him taking an interest in what's going on," he said carefully. "He certainly wants to talk to you. He's in his cabin, if you'll come with me."

"I'm sorry about what happened to your ship," said Nelson, as soon as the introductions had been made.

"It was no fault of yours, Admiral," Kirienko responded sombrely. "I am only thankful that help was so close."

"How many men did you lose?" Nelson asked, with almost brutal directness.

"Five," replied Kirienko. "The crew of a surveillance trawler is not large -- but three of them were good friends and comrades."

"I'm sorry," Nelson said again. "It was a terrible thing."

"What about the other two?" asked Crane, realizing after a moment that the Admiral was in danger of losing himself in his own dark thoughts. He checked quickly that Bradley was still within call; he had had his doubts about the wisdom of this interview, but the Admiral, refreshed after a brief rest, had insisted on taking part.

"They were specialists assigned for the mission," Kirienko explained. "I had known them only a few weeks." Bitterness edged his voice. "It was they who brought the Serpent upon us."

"You'd better tell us from the beginning," said Nelson, returning to the present with a visible effort.

"How much do you know of the Serpent?" Kirienko asked.

"Enough," Nelson said grimly.

"We've been following it for a couple of days," Crane added, "and monitoring the control signals. We know it belongs to Kwaishan, but we aren't quite sure yet how they intend to use it. Our brief is to follow and observe it, "

"Then you know almost as much as we did," said Kirienko. "Perhaps more -- until today we had not seen the beast at close quarters. But our 'experts' thought they knew enough to control it -- turn it from its determined course, and so prevent whatever it was to do. You saw the result."

"It was you off the Western coast of Kwaishan five days ago?" asked Crane.

"And for some time before that," Kirienko confirmed. "We had learned of the Serpent, and were waiting for it to set out on its journey."

"There seems to have been a certain duplication of effort," observed Nelson.

"Certainly it would appear that both our governments had the same objectives in this matter," Kirienko said cautiously.

"But your intelligence operations in Kwaishan were rather more successful." Nelson frowned, rubbing his forehead. "What would you say to combining our resources?" he asked after a difficult pause. "You have information, and we have Seaview -- and once our engine trouble is straightened out, we should be able to follow the Serpent pretty closely."

"I also have personal reasons for wanting the creature destroyed," Kirienko pointed out, "but I do realize that there are larger issues at stake. I would be honoured to assist, Admiral, as far as I can."

"How long has Admiral Nelson been in this condition?" Kirienko asked abruptly, as he and Crane were studying the charts that showed the Serpent's course.

Crane looked up, startled by the change of subject, and still not sure that he wanted to discuss the Admiral with an outsider.

"I do not wish to intrude," said Kirienko. "I ask only because I think I may have a possibility to help him."

"We can't talk about it here," Crane managed to say. Suddenly it was hard to keep his voice steady; the unexpected surge of hope had turned him a little dizzy.

"My cabin, then?" Kirienko suggested.

"All right."

The quarters assigned to the Russian were those normally occupied by visiting scientists and other experts, larger and more comfortable than any other cabin except the Admiral's own, but as bare of personal things as a hotel room.

"Now, Captain," Kirienko invited, "sit down and tell me everything."

Partly because he dared not let slip any chance of helping the Admiral, and partly because he desperately needed to talk, Crane obeyed. He tried to be brief and impersonal, but at times he found himself going into more detail than was strictly necessary. Kirienko was an excellent listener, and the sympathy in his occasional interjections sounded genuine.

"The Admiral must be a remarkable man," he said at last. "To come so close to normal functioning in such a short time, and without any real treatment -- that must need great courage and strength."

"He is . . . remarkable," Crane agreed, "but I don't know how long he can keep it up. You said you might be able to help?"

"Yes," said Kirienko. "There is an antidote to the drug. It is a pity that your people do not know of it."

"An antidote?" Crane echoed. "You mean -- something that could cure him?"

"As long as he has not already suffered too much psychological damage," said Kirienko. "From what you say, I think he has a good chance of a complete recovery."

"Just tell me what this stuff is," Crane said fiercely, "and I'll see he gets it if we have to go halfway round the world to find it."

"There is no need for that," Kirienko responded. "I have some here." He opened a drawer and brought out a battered stainless-steel hip-flask.

"What . . ." Crane accepted the flask, unstopped it and sniffed at the contents. "Vodka?" he asked incredulously.

"Ordinary Russian vodka," Kirienko confirmed. "It is not the alcohol, you understand --there is a trace chemical which is the antidote. It was a chance discovery in the first instance. One of our agents was subjected to the drug. His partner rescued him, but he was quite mindless. The partner had no other way to keep him from harming himself, so he made him drink much vodka, hoping he would at least sleep for a while. It worked better than he had hoped: the man slept for a day and a night, but when he woke he was perfectly well. The scientists isolated the active ingredient, later, and made it into a simple injection, but the vodka works just as well. There should be enough in the flask."

"It sounds almost unlikely enough to be true," Crane murmured, staring at the flask.

"Believe it," Kirienko urged.

"Oh, I want to believe it. But if we give this to the Admiral -- even assuming we can persuade him to drink it -- and it doesn't work, he could end up in worse shape than he is already."

"And if you do not," Kirienko pointed out, "he could have another relapse tonight, or the next night. How much longer can you go on, dealing with his nightmares night after night? Sooner or later, something will give way."

"I know," Crane admitted drearily. "We haven't really much to lose. I'll talk it over with the Doctor."

"That is sensible," said Kirienko.

"Don't get me wrong." Crane rose, rather reluctantly; sitting for a while in a comfortable chair had made him realize how tired he was. "I do appreciate the help -- and after what you've been through today I wouldn't blame you if you wanted to keep the stuff for yourself."

"I owe my life to Admiral Nelson," the Russian said gravely. "Also, I know something of what he must be suffering, and I would not wish that on my worst enemy."

"They used the drug on you?"

"Two years ago. It is not a good memory -- they told me it was only five days, but it felt like forever, as if there had never been anything else, only darkness and horror. But -- as you see -- I made a complete recovery."

"I see," Crane said slowly. It hardly amounted to proof in the legal sense, but it certainly added weight to Kirienko's assertions. "Thank you." Slipping the flask in his pocket, he headed for Sick Bay.

"It's certainly possible," the Doctor said, looking rather dubiously at the dented flask, "and I doubt it could do much harm, under proper supervision -- that is if it is just vodka and not laced with some kind of poison."

"Now why would Kirienko just happen to be carrying a flask of poisoned vodka when his ship was wrecked?" asked Crane.

"It doesn't seem very likely," admitted the Doctor, "but I'd like to run some tests on a small sample, just to be sure, before we say anything to the Admiral. He seems to be fairly stable at the moment, and there's no point disturbing him with false hopes."

"That seems fair enough," Crane agreed. The last word came out as a yawn.

"As for you, Captain," the Doctor said severely, "I strongly recommend that you try to get a few hours' sleep."

"I can't do that," Crane protested, rubbing his hands over his face. "I've been away from my normal duties for too long as it is -- after what happened this morning there's a lot that needs seeing to."

"You'll be no good to the Admiral or anyone else if you run yourself completely into the ground," the Doctor warned. "You haven't slept for more than a couple of hours in the last two days. You can't keep that up for much longer, and the chances are the Admiral will need you tonight, one way or another."

"Oh, very well," Crane said wearily. "I suppose Chip can handle things for a while." The bunk a couple of feet away did look very inviting. "Wake me in an hour, Doc," he mumbled. He was asleep before he heard the answer.

He woke, stiff and headachy, to the sight of the Doctor standing over him with a syringe.

"I don't like doing this," the Doctor said, "but it is an emergency."

"What? What time is it? Crane asked drowsily. "What are you doing?" Suddenly he was fully awake, rubbing the needle-mark in his arm. "What time is it?"

"It's 0200 hours, Captain."

"What? Where's the Admiral?" He had not intended to sleep for nearly so long.

"He's in the Observation Nose," said the Doctor. "He wants to talk to you, Captain."

"At two o'clock in the morning? What sort of emergency are we talking about?"

"He has a gun," the Doctor said baldly. "No, sit down and listen a moment. Bradley's with him now, but he insists on talking to you. He spent most of the afternoon in his quarters, and about five o'clock he fell asleep. We thought it would be better not to disturb him. Bradley volunteered to stay with him after the end of his watch. About midnight he got up, went to his desk and fetched a pistol. We don't know if he was really awake at that stage, but he had the gun out and loaded before Bradley could stop him. Then he went down to the Observation Nose and sat down in his usual chair."

"Two hours ago? Why wasn't I told at once?"

"We did try waking you, but it was no good. He wasn't doing any harm -- just sitting there, staring out of the window -- but we didn't know what would happen if we tried to interfere. Eventually he started asking to see you, so I tried again. I had to give you a shot to wake you up: it should keep you alert for a couple of hours."

"Right," said Crane grimly. "I'll go and talk to him. What about the antidote?"

"We have to try it, if you can persuade the Admiral. We can't go on like this. If you bring him down here, I'll have it ready."

The collision screens closed off the Observation Nose from the rest of the Control Room. The lights were low; the water outside the window was a deep blue-black, with streams of shining silver bubbles flowing upwards. Nelson sat hunched in his chair, turned sideways so that he could see both inwards and outwards; the sidearm was cradled in his lap. He looked tense, bewildered, and dangerous as a wounded animal at bay.

"Admiral?" Crane said quietly, stopping several yards away and holding out his empty hands. "You wanted to talk to me?"

"Lee?" Nelson seemed to relax a little, but he did not drop the gun. "I'm sorry," he said uncertainly. "I didn't know what else to do."

"What's bothering you, sir?" asked Crane, coming slowly closer.

"I can't go on like this," Nelson said simply.

"Why don't you give me the gun," Crane suggested, "and we'll talk about it."

"Gun?" Nelson echoed, startled. "Yes -- take it. I'm not sure what I was doing with it anyway."

"That's better." Crane took the weapon from Nelson's slackened grasp, and quickly unloaded it. "Bradley," he ordered, "take this away -- and then go to your quarters."

"Aye, sir." The corpsman came over, accepting the gun rather gingerly.

"You've done a good job," Crane assured him, "but you've been on duty for long enough."

"Go on," Nelson put in, "and don't worry. You did everything you could, and I'm very grateful for your help."

"You haven't shot anybody, if that's what's eating you," Crane said when the corpsman had gone.

Nelson breathed a long sigh. "That was part of it," he admitted, "but I could have -- and next time I might. We have to face facts, Lee -- letting me run around loose is getting to be an unacceptable risk."

"You are doing a lot better than you were," Crane pointed out. The calm, reasoned despair in the Admiral's voice was terrifying. "If we were going to lock you up we'd have done it days ago -- and then what would we have done when the reactor started playing up?"

"You'd have thought of something," Nelson said wearily. He fell silent for a while, gazing out into the dark water. Crane settled himself on the broad ledge below the window and waited. "I don't know how much longer I can stay even half sane," Nelson said at length, very quietly. "The things I see, even when I know they can't be real . . . some of them aren't so bad, but some of them are terrible. Every time I look at you, I see you bleeding to death, and knowing it isn't true doesn't make it any easier to bear -- I know that you've been wearing yourself out looking after me. And the rest . . . not just monsters, but blood and corpses and flames everywhere I look. Everyone keeps telling me that everything's all right, that it's safe here . . . but that isn't the point. It isn't true, and everyone knows it -- this ship is about the least safe place there could be."

Crane made a protesting noise, unable for the moment to think of a suitable answer.

"Do you know how many men have died on this ship in the last year?" Nelson asked. "No, don't bother reckoning it up -- I already did. Thirty-seven crew, six prisoners, and four visitors -- people we were supposed to be helping -- plus four intruders. Fifty-one lives in one year."

"Look at it another way," said Crane. "Think of all the millions of lives we helped to save, one way and another. The crewmen are volunteers -- they know the risks -- and most of the others brought it on themselves. I've never known you waste a life, sir."

"Maybe," Nelson murmured, only half convinced. "But I can't do it any more -- how can I go on taking those sorts of decisions when it takes me all my time to decide it's safe to walk down a corridor? It's no good, Lee: I'm finished, and we both know it."

Crane took a deep breath, realizing that the time had come. "What you need," he said as naturally as he could, "is a stiff drink."

"What?" Surprise jolted Nelson out of his despondency: he sounded almost amused even in his indignation. "Have you been listening to a word I've been saying?"

"I've been listening, Admiral, and I agree you can't go on like this. The point is, you don't have to: we finally found the antidote to the drug."

"Alcohol? But surely . . ."

"Not just any alcohol," Crane explained. "Russian vodka. Apparently the KGB has known about it for years, which probably explains why their intelligence gathering in Kwaishan was more successful than ours."


"Exactly. He not only knew about it -- he just happened to have about half a pint of the stuff in his hip-flask.

"Do you trust him?"

"I let Doc check the stuff out to make sure -- but yes, I trust him. He seems like a regular kind of guy, for a Communist."

"All right," said Nelson, after a pause. "It has to be worth a try."

"Right," said Crane, hugely relieved to have gained the Admiral's consent so easily. "Let's go."

The walk back to Sick Bay gave Crane a new respect for Bradley's patience. Nelson was obviously trying very hard, but he could not keep himself from swerving around illusory obstacles every few yards, and once he insisted, rather apologetically, on a detour to avoid a particular staircase. By the time they reached their destination, he seemed to have come to the end of his endurance; he sat on the edge of his usual bunk, limp and shaking with exhaustion, and did not bother to protest when Crane lifted his feet from the floor and tucked a pillow behind his head.

"Let's get this over with," he said presently.

"Apparently you should sleep for about twenty-four hours," said the Doctor, pouring the clear liquid carefully into a medicine glass.

"Then we'll have to hope that the Serpent doesn't do anything tomorrow," Nelson said, with a fair imitation of cheerfulness. He accepted the glass and took a cautious sip. "I suppose ice and lemon would be too much to expect."

"Medicine isn't supposed to taste too good," Crane responded.

Nelson finished the contents of the glass slowly, but without further comment, and held it out for a refill. The second glassful seemed to go down more easily: the final half-glass, the last of the flask, he drained in a couple of gulps. A few moments later, he mumbled something unintelligible and slumped sideways against the pillow, completely relaxed at last.

"I don't think we should tell the crew about this," Crane murmured, smiling in bemusement.

"Of course not," the Doctor agreed. "I just hope it works. Now, you'd better get to your quarters before that stimulant wears off."

"I already slept for nearly ten hours," Crane protested.

"You were completely exhausted -- physically and emotionally," the Doctor told him. "It's going to take more than a few hours' sleep to get over that, but if you do as you're told now I just might let you go back on duty in the morning."

"What about you?" Crane asked. "You can't have been getting much more sleep than I have, these last few days."

"I haven't got a ship to run," the Doctor replied. "I can sleep any time I'm not needed -- it's all part of the job. You, on the other hand, have been trying to do the work of at least two men, if not three, for the last week. If your Russian friend hadn't come along when he did, I dread to think what would have happened. Now get out from under my feet, will you?"

"You were going to tell us about the Serpent," Crane reminded Kirienko the next day.

"Of course, Captain. I hope you are well rested now?"

"I should be," Crane said cheerfully. Rather to his embarrassment, he had slept well into the morning, but it did not seem that he had missed anything of importance. The Admiral was still unconscious, but the Doctor reported that the level of the drug in his bloodstream was falling steadily. Repairs on the damaged engine were almost complete, and the Serpent, though well ahead of the Seaview, was still within range of the tracking device and keeping to its course. The atmosphere in the Control Room was undeniably tense and uncertain; the Admiral's absence from his usual chair had not gone unnoticed, and a number of wild rumours about the previous night's events had begun to circulate among the crew. However, the Captain's reappearance did much to reassure the men.

"Of the Serpent itself, I do not know so very much more," Kirienko admitted, when he and Crane had settled themselves at the table by the observation window. "There are other things that may interest you, however. Did you know that there are two areas of knowledge where government scientists from Kwaishan are far ahead of the world? One is the genetic engineering of marine life. The other is plate tectonics -- the study of the Earth's crust and the great faults along which it moves."

"That seems an odd combination," Crane commented, not sure where this was leading.

"They have very little knowledge of nuclear devices," Kirienko continued, "no more, perhaps, than what an ordinary international terrorist might have these days. That, we believe, is why they stole the warhead. But the plan to use the device -- that has been years in the preparation. The Serpent is the ideal delivery system -- almost undetectable, and completely unexpected by most of the world."

"But why deliver a bomb to the middle of the ocean?" Crane demanded.

"Look here." Kirienko ran a finger down the chart, following the long, narrow area of unmapped deeps. "This trench is at the junction of two parts of the Earth's crust. The boundary of this plate runs here." He picked up a pencil and sketched in a rough circle, with its Western circumference crossing the China Sea not far from the island of Kwaishan. "It is our information that they intend to set off an explosion in the trench that would cause the plate to shift a little."

"Surely that would cause earthquakes and tidal waves all over the globe!" Crane exclaimed, staggered by the enormity of the idea.

"Precisely," Kirienko confirmed gravely.

"What would Kwaishan stand to gain? Wouldn't their little island be in as much danger as anywhere?"

"That is the cleverness of the plan. As we understand it, they believe that if the site of the explosion is correct, the size of the island of Kwaishan would be more than doubled with very little damage, while every other power in the region would be devastated and destabilized."

"So where is this correct site?" Crane enquired, studying the map. The great trench was not much more than a day's sailing away, and the Serpent had a lead of several hundred miles.

"Unfortunately, we do not know precisely," Kirienko confessed. "Our scientists had some calculations, but I do not have them here -- all my notes went down with my ship."

"We've got a lot of catching up to do," Crane said grimly. "We can still make it -- if the engine is fit to go within the next couple of hours, and we run at flank speed all the way."

"The Serpent does not yet have the warhead," Kirienko reminded him. "It must go first to the ocean base -- wherever that is. Our information is that the warhead was never taken to Kwaishan. We lost track of it after it was loaded aboard a small steamer heading for this area of the Pacific."

"They must be using an island," Crane mused. "They wouldn't have the resources for an underwater installation -- that would need a submarine to service it, and if they had a submarine they wouldn't have to mess around with the Serpent."

"We certainly have no information that they have submarines," Kirienko confirmed. "An island certainly seems the most likely solution."

"But which island?" Crane frowned at the chart. "There are hundreds of them out here -- and not all of them are marked on the charts. I suppose we can rule out the larger inhabited ones." He sketched in what seemed likely to be the Serpent's course: there were at least a dozen small islands along the line.

"There is one possibility," Kirienko said slowly. "The control signal -- it comes from Kwaishan, but surely soon they will begin to transmit from the base instead. If you could identify the changeover and pin-point the source of the new signal . . ."

"We might be able to jury-rig something," Crane said guardedly.

"You mean that my little trawler could do things your beautiful submarine cannot?" Kirienko asked, amused.

"I didn't say we can't do it," Crane responded, "but it may take a little thinking about. I'll get Sparks to look into it straight away."

It was just under an hour later that the engine repairs were finally complete.

"Will it stand up to a long run at flank, Chief?" Crane asked a little anxiously.

"As well as it ever would, sir," Sharkey replied. "There's a complete new turbine blade in there: short of replacing the whole engine, we couldn't have done any more if we had a week in dock to do it."

Little by little, the Seaview gained on her quarry; by evening the Serpent's lead was just over two hundred miles, and it had shown no deviation from its predicted course. Kirienko's theory about the second control signal remained unconfirmed as yet. It was becoming obvious, however, that the original signal was approaching the limit of its range. The Admiral was still sleeping, though he had twice woken briefly, swallowed a little water and gone back to sleep. Crane went to his cabin fairly early, leaving orders that he was to be woken if anything happened, but very much looking forward to a night's unbroken rest.

Just before four the next morning, Nelson woke fully from his long sleep, alert, cheerful and ravenously hungry. He devoured the toast and cereal which the Doctor considered suitable after such a long abstinence, and then demanded his clothes, impatiently brushing aside the idea of going back to sleep for what was left of the night. He spent the next hour or so wandering all over the ship, assuring himself that everything was as it should be, with no horrors lurking in shadowy corners. He was rather surprised at how bright the corridors seemed; he had spent days seeing everything through a film of illusory darkness. Such of the crew as he encountered on his peregrinations reacted at first rather warily, but then, when they realized that he was really himself again, with genuine delight. Eventually, after a brief inspection of the Control Room, he came to rest in his accustomed seat by the observation window, watching the gradual brightening of the water as morning approached. The Serpent was in its place again, a deeper shadow a few hundred yards away in the ultramarine depths, a reminder that the mission was not yet over, that the most difficult part might be still to come. When Crane joined him at the window, an hour or so later, Nelson was poring over two charts, a computer printout and a sheaf of notes.

"Good morning, Admiral," Crane said cheerfully. "You're looking a lot better."

"So are you," Nelson retorted, pushing aside his work. He was relieved to see that Crane was not only free from illusory bloodstains but also thoroughly rested. "In fact, everything looks wonderful -- with the possible exception of that thing out there."

"Have you any ideas about that, sir?"

"Have you? This is supposed to be your mission, after all."

"We can get that little matter sorted out the next time we call Washington," Crane said quickly. "Perhaps we should just destroy the Serpent -- we know by now that it isn't carrying the warhead yet."

"It's too late for that," Nelson said sombrely. "It would take a massive explosion to be sure of destroying that creature, and in these waters that could cause exactly the kind of destruction we're trying to prevent. The Earth's crust is very thin here, and none too stable. Any kind of large explosion would set off tidal waves and earthquakes over a huge area."

"Kirienko thinks that's what Kwaishan is trying to do," Crane remarked, studying the marks that Nelson had made on the chart. "So we just keep tagging along?"

"For the moment I don't see what else we can do," Nelson confessed. "After what happened to Kirienko's ship, I don't fancy our chances of controlling the creature ourselves. In the meantime, I could do with something to eat -- like a small horse."

"I don't think the galley has any in stock," Crane said, smiling, "but I'm sure they'll do their best."

"Lee," Nelson said suddenly, pausing in the act of gathering his papers together, and speaking in a quite different tone of voice. "The other night . . . I seem to remember talking a lot of nonsense."

"Don't worry about it, Admiral. It won't go any further. Just think of it as another nightmare that's over and done with."

Kirienko's speculation about the second control signal was confirmed quite early in the morning. As the source of the new signal appeared to be almost dead ahead, it added little to what was already known of the Serpent's course. There was no land marked on the charts in that direction, but the sea was scattered with so many tiny islands, many of them volcanic, that this was not too surprising. Just before noon, the crewmen on sonar watch reported a large, stationary obstruction ahead.

"It looks like we've arrived," Crane remarked, looking out of the window at the shadowy mass in the distance.

"It seems to be a volcanic island," Kirienko observed.

"There's no sign of any volcanic activity at the moment," Nelson said thoughtfully, studying a slip of computer output.

"Where's the Serpent?" Crane asked suddenly. The rearing wall of the island's base was well within visual range now, but the creature was nowhere to be seen.

"It can't just have disappeared," Nelson said, but there was a note of uncertainty in his voice. He had grown too used to not trusting the evidence of his senses to be quite sure of anything.

Crane went quickly to the instrument panel monitoring the beacon that the Serpent still carried. "That can't be right," he muttered. "It seems to be carrying straight on -- inside the island!"

"Well, obviously there must be a tunnel," Nelson suggested, coming to check the readings.

"Can we follow?" Kirienko asked.

"Into an underwater tunnel we know nothing about?" Crane demanded. "The Seaview is twice as wide as that creature, and not nearly as flexible: we'd be taking an awful chance."

"What are the alternatives?" Nelson enquired. "Either we sit out here and wait, like a cat at a mouse-hole, while the Serpent slips out through another exit and gets a lead we can't catch up -- or we send divers, or the Flying Sub, into the tunnel. That might let us keep tabs on the Serpent, but it wouldn't give us much chance of doing anything else."

"Then you want to go into the tunnel, sir?" Crane asked. "What happens if we can't get through?"

"Then we back up and think of something else," Nelson replied calmly. "We have to try -- and it probably is wide enough. You've seen the way the creature moves -- it needs quite a lot more room than its own cross-section."

"Aye, sir," Crane said resignedly. It felt very good to have the Admiral taking charge of the situation again, but he was not very happy about sailing the submarine into what could well be a blind alley. "We'll have to take it very slowly," he warned.

The entrance to the tunnel was three hundred feet underwater, a vast natural cavern in the cliff that swallowed the submarine easily. Farther in, it narrowed to about a hundred feet in diameter. Inch by inch in the darkness, completely dependent on her instruments, Seaview crept forward.

"You see," Nelson said cheerfully. "We've got all the space we need."

"Admiral," Kirienko asked abruptly, "is there any possibility that we are expected?"

"I don't know," Nelson admitted. "I suppose they might have guessed that we'd follow the Serpent. They do have a fair idea of the Seaview's capabilities, I'm afraid." For a moment, the haunted look was back in his eyes.

Crane, intent on the instrument panels, heard this exchange and experienced a few seconds of awful doubt. Perhaps, after all, it had been a mistake to follow the Admiral's suggestions without question.

"It doesn't make any difference," Nelson said after a moment. "We had to go after it, and we ought to be able to handle anything they can throw at us."

"Well, we'll soon find out," Crane said tensely. "This is the end of the tunnel -- the only way out is up."

"Take us up to periscope depth," Nelson ordered. "We might as well see what we're getting into."

Crane gave the necessary orders, and the submarine rose slowly between the walls of a widening rocky shaft. Soon, a little light began to filter down, green-tinged, revealing nothing.

"Well?" Crane asked, when the Admiral had spent a minute or so looking through the periscope. "Can you see anything, sir?"

"This is their base, all right," Nelson responded. "Take a look for yourself."

Crane took the Admiral's place at the eyepiece. At first it was hard to make sense of the view; wherever he turned the periscope he saw a thickly overgrown shore, backed by overhanging rocky walls, lit by dim, green-tinged sunlight. Gradually he realized that he was looking at a kind of lagoon, no more than five hundred yards across and completely surrounded by what must once have been the cone of the volcano. At one side, a few rough stone buildings clustered against the walls, with a tangle of wires and antennae stretching up towards the hidden sky.

"Where is the Serpent?" Kirienko asked.

"Skipper, the beacon's gone dead," reported the crewman who had been monitoring it.

"Well, they'd hardly leave it in place," Nelson pointed out. "It doesn't matter now -- it served its purpose. It looked to me as though the creature's over there by the huts. Do we still have sonar contact?"

"Negative, sir," Kowalski said, frowning over his screen. "We're too closed in -- there's no making any sense out of the signals now."

"No need," Crane said grimly. "It's on the surface and heading straight for us." Hastily he pulled the periscope down. "Take us down to two hundred feet," he ordered sharply. "Rig for collision."

"Is it loaded?" Nelson enquired, jumping nimbly down from the periscope platform.

"It looks like it," Crane said tersely.

"Then they won't try to ram us," Nelson asserted. "They won't want to risk exploding the warhead in here."

Crane nodded, acknowledging the sense of this. "Hard right rudder," he ordered. "Ahead one third." If the Serpent was heading for the tunnel again, he wanted to follow it as closely as possible.

"Skipper," the radio operator called suddenly, "they're trying to make contact."

"All right, patch it through," Crane responded. It had been too much to hope that they could bring the submarine in and take it out without being noticed.

"Kwaishan research station calling S.S.R.N. Seaview," a voice crackled from the speakers.

Nelson raised an eyebrow at that, but passed the microphone to Crane without audible comment.

"This is Seaview," Crane said calmly.

"You have done well to find us," the voice replied, a note of mockery discernible even through the thick foreign accent, "but it was foolish to venture into this lagoon. You will not be able to leave as easily as you came in. You see, we know exactly what your submarine can do -- your Admiral was most forthcoming under interrogation -- and we were prepared for this. You cannot use your weapons here. You will surface and await a boarding party."

"What happens if we refuse?" Crane asked. They were almost back at the shaft opening; around him, crewmen were hurrying to battle stations.

"You cannot remain underwater for ever. Sooner or later you must come to the surface -- unless you prefer to have your entire crew die of suffocation. There is no escape for you now." The voice shut off with a click of dreadful finality, like the sound of a trap snapping shut. A few seconds later, the proximity alarm began to sound. Crane barked an order, and the submarine came to as abrupt a halt as was physically possible.

"Skipper," Kowalski said urgently, looking up from his screen with a frown of puzzlement, "the opening's gone!"

"You're sure?" Crane asked, coming to study the display.

"Positive, sir. This is where we came in -- but it doesn't look like we can get back out."

"There must be some kind of gate," Nelson said, considering the problem. "Let's cast a little light on the situation."

With the crash doors closed, and the lights in the Observation Nose extinguished, the submarine's nose lamp lit up the water outside and revealed the nature of the obstacle -- a grille of metal bars, six inches thick and only about two feet apart, filling the entire tunnel.

"We could send out divers with cutting equipment," Crane suggested.

"That might work," said Nelson, "but it would take too long. We can't afford to let the Serpent get too much of a lead."

"Without the tracking device, we can't even afford to let it get out of sight," Crane agreed.

"It's not quite that bad," Nelson assured him.

"No? Admiral, if you know something I don't . . ."

"I don't," Nelson said cheerfully, "at least not yet. But I'm expecting a call from Washington in the next few minutes. If they can give us the information I requested, we should be able to figure out where to go from here. But we haven't much time to spare. If that warhead is primed -- and as far as we know they've no way of doing that remotely -- it can't be more than two hours from detonation. Cutting through those bars would take longer than that."

"We can't blast our way out," said Crane. "An explosion in this tunnel would destroy the ship -- even if it didn't bring several thousand tons of rock down on us."

"May I suggest?" Kirienko said tentatively.

"A suggestion right now would be very welcome," said Crane.

"There must be some remotely controlled mechanism that operates the gate," Kirienko pointed out. "If your divers could find that, and override it . . ."

"I think you're on the right track," said Nelson, frowning through the window. "There seems to be some kind of lever arrangement over to the left."

"Chip," Crane said immediately, turning to Morton, "I want a team of divers out there on the double -- with tools and cutting equipment."

"Aye-aye," Morton responded, rather bemused by the sudden rapidity of events.

"Will Washington be able to contact us in here?" Crane wondered aloud.

"They'd better be." Looking suddenly weary, Nelson moved over to the table and sat down.

"There should be no problem," Kirienko offered, taking a chair himself. "A signal strong enough to cross half an ocean will not be stopped by a few metres of rock."

Nelson grunted an acknowledgement, already almost engrossed in the charts he was studying. He pencilled in the position of the island, then began scribbling down equations. After a moment, Kirienko reached for pencil and paper and began some calculations of his own. Crane watched the pair of them for a moment, before going off to check the instruments and give certain orders. If Nelson was surprised, a few minutes later, to find a crewman at his elbow with a laden tray, he did not comment on it; he thanked the man and dismissed him, and continued with his work even while he ate. Outside the window, in the floodlit water, three divers worked on the gate mechanism. Their comments, relayed over the Control Room loudspeakers, crackled in the waiting silence.

The expected radio message came through exactly on schedule, weak and muffled but understandable. As soon as he was given the transcript, Nelson began marking a complex pattern of numbers and lines on the chart, his hand moving so quickly that the pencil-point snapped. He tossed the useless implement away impatiently. At once, Kirienko handed him another, then picked up the second page of the transcript and started marking a different area of the chart.

"What's all this about?" Crane enquired, coming to see what they were doing while still keeping one eye on the activity of the divers.

"The dynamics of the ocean floor," Nelson said briefly, finishing his drawing. "I asked for some detailed data on this area. It shouldn't be too hard to work out where they have to plant their bomb -- and where we have to set the counter-explosion."

"I'm afraid you've lost me," Crane admitted, frowning over the spider-web of markings. "What counter-explosion?"

"There's no way we can stop that bomb going off," said Nelson, as if this should have been obvious all along. "Maybe if we could have stopped the Serpent in time to start disarming the warhead . . . but it's too late for that now. Our only hope is to rig another explosion to go off at exactly the right time, so placed that the effects of the two will cancel out." He scrawled down a few more calculations, then placed a finger firmly on a spot about seventy miles from their current position. "There."

"I agree," Kirienko put in, "but I see one problem with your plan, Admiral."

"Oh?" Nelson gave him a sharp, enquiring look.

"If your explosion is here," said Kirienko, placing his thumb on the spot Nelson had indicated, "and the Serpent places its bomb here --" pointing out the place with the forefinger of the same hand, "-- how can you know what the right time is?"

"We can't," Nelson said flatly, "but we can place certain limits on it. We have a fair idea of the creature's speed: I'd say it couldn't possibly reach the target area in less than an hour and a quarter -- more likely an hour and a half. We know that the warhead has only a two-hour timing device, which must have been started about a quarter of an hour ago. That means the explosion must be scheduled for some time between 1345 and 1400 hours."

"Is that good enough?" Crane asked.

"I do not think so," said Kirienko. "According to my calculations, if the counter-explosion is mis-timed by more than two minutes, its effects will add to those of the original explosion rather than cancelling them. So we have only one chance in five of being close enough, if we simply guess."

"Have you any better ideas?" Nelson asked, sagging a little.

"Not at present," Kirienko admitted.

"It wouldn't be the first time you've had to make a guess, sir," Crane said encouragingly, "and we're still here." He knew, however, that he was trying to convince himself as much as anyone else.

"I'm afraid he's right, Lee," Nelson said quietly. "If I guessed wrong, we could do more harm than good -- maybe tear the whole planet apart at the seams. And if those divers don't get the gate open in about the next two minutes, we'll probably be too late anyway."

"What about the Flying Sub?" Crane suggested. "If I went out and followed the Serpent, and radioed back when the explosion went off . . ."

"Anything within visual range of that explosion is likely to be totally destroyed," said Nelson. "I can't let you run that risk."

"In the circumstances, I think it would be a chance worth taking," Crane said, a little surprised.

"If anyone were going to try a stunt like that, it ought to be me," said Nelson.

"Skipper! It's moving!" The diver's exclamation broke into what was on the verge of becoming a heated argument.

"Good work. Now get back on board, on the double," Crane responded, watching as the gate rose slowly to the roof of the tunnel. "Prepare to get under way as soon as the diving party is aboard," he ordered. "And get the Flying Sub ready for launching."

"Belay that," Nelson snapped.

"Sir?" Morton looked from the Captain to the Admiral, confused.

"We won't be needing the Flying Sub," Nelson said firmly.

For a few uncomfortable seconds, Crane wondered whether the Admiral was losing his nerve. It would be understandable, after what he had been through recently, but at this juncture it was potentially disastrous. It was very unlike him to balk at risks in such a situation.

"The control signal!" Nelson exclaimed suddenly, straightening in his chair. "Of course! They can't relinquish control of the Serpent until the bomb is on the point of explosion. Once the signal stops, we'll know that it's time."

"All right," Crane said, relieved. He noted down the co-ordinates of the counter-explosion site. "What kind of explosion had you in mind, sir?"

"A couple of nuclear depth charges should do the trick," Nelson said briskly. "We just have to drop them into the trench and pull back to a safe distance."

It was more difficult to negotiate the tunnel, going out, than it had been coming in; all the corners and gradients seemed to be against the submarine. It took a tense quarter-hour before the Seaview was back in open water, with a few scratches on her hull but no serious damage.

"There's only just enough time," Nelson observed.

"I'd noticed," Crane said dryly. "Let's get going. All ahead flank!" He did not like to think what would happen if they ran into any delay now; at full speed they would reach the target area with only minutes to spare.

They had covered barely half the distance when the control signal, which Nelson had ordered to be relayed over the main speakers, suddenly faded out.

"That's impossible!" Nelson exclaimed. "The Serpent can't have got there yet!"

"Perhaps our calculations were in error," Kirienko suggested, at a loss for the first time.

"No, no," Nelson said impatiently. "We both came up with the same figures -- the odds against that must be astronomical. There must be some other explanation." He got hastily to his feet and went over to the radio shack. "Sparks, what happened?" he demanded.

"I'm not sure, sir. Could be a malfunction in our receiver -- I'm just checking it now."

"We need that signal," Nelson said urgently. "Without it we've no chance of getting this right."

"One chance in five isn't that bad," said Crane.

"It isn't good enough to rely on," Nelson retorted, watching as Sparks flicked switches and twisted dials to bring in the back-up receiver.

"Why do you not check the amplifier?" Kirienko said suddenly. "Connecting it to the loudspeakers could have caused an overload." He reached out and pulled a unit from the rack with an expert hand. "You see?" He pointed out a charred component.

"If only all our problems were that simple," said Crane, almost laughing in his relief.

"I'm afraid it isn't quite that simple, Skipper," Sparks said unhappily. "We haven't got a spare for that board, and it would take at least an hour to wire up a replacement."

"There is no need for that," said Kirienko. "With your permission, Admiral?"

"Go ahead," said Nelson, smiling faintly.

Kirienko's methods seemed to owe a great deal to the experience of working with very limited resources, but they were effective. Within less than five minutes he had jury-rigged a crude but adequate amplifier. The complicated fluting of the signal, a little distorted by the limited bandwidth of the makeshift circuit, blended once more with the Control Room's usual hum of sonar blips and engine noise.

"Sometimes the simple solutions are the best," he said when he was done.

"Of course," Nelson responded, giving him a friendly clap on the shoulder.

There was no doubt as to when they reached the trench. Within less than a hundred yards, the ocean floor dropped away to depths that Seaview's instruments could not measure.

"If we go out of control here, we're dead," Crane said quietly, studying the view relayed from the camera in the base of the hull. The abyss was full of shadow, blacker than a starless night; even at full power the floodlights did not penetrate more than a hundred feet down.

"Relax," Nelson advised cheerfully. "If anything goes wrong now, the trench will be the least of our worries."

"Missile Room," Crane said, picking up the microphone, "this is the Captain. Are the depth charges ready for launching?"

"Armed and ready to go, Skipper," Sharkey responded.

"Stand by," Crane ordered.

The control signal carried on, more complexly cadenced now. Crane perched himself on the edge of the table, microphone in hand, ready to give the order to launch the charges. He could not take his eyes from the monitor screen that showed the trench; he had some uncomfortable memories of things that had emerged from such places. Kirienko also seemed fascinated; he was muttering softly to himself in Russian, forgetful of his companions. Nelson sat with his head tilted slightly to one side, tapping his pencil on the table in imitation of the control signal's rhythms.

"Soon," the Admiral said presently. His pencil tapped a few more times, softer and slower, then stopped. He held up a hand in the sudden silence. "Now!"

"Fire depth charges," Crane ordered at once.

"Depth charges away," Sharkey's response came, seconds later.

"All back full! Rig for shock waves."

As the nuclear devices fell into the abyss, turning silently and unseen in the unimaginable depths of darkness, the submarine moved back from the brink. It was nearly a minute later when the charges detonated. The force of the explosion tossed the Seaview around like a leaf in a hurricane, flinging men around the Control Room. Inevitably, the motion caused short circuits and a few minor fires, and for a minute or two the room was full of smoke, ruddy in the emergency lighting. Then the vessel steadied, and the normal lights came up.

"This kind of thing happens often?" Kirienko enquired breathlessly, picking himself up.

"All the time," Crane assured him. "Damage Control, report!"

"No serious damage, sir," came the reply.

"Well, did it work?" Crane asked then, going over to join Nelson at the panel of seismological instrumentation.

"Perfectly," Nelson replied. "There's no sign of any crust disturbance at all. I think we can call this a success for international co-operation."

"Unfortunately," Kirienko observed, straight-faced, "there is no possibility to celebrate this success properly, now."

"Oh, I think we might find something in the drinks cabinet," Nelson responded. "Not vodka, I'm afraid, but maybe something you'll like better. I shan't forget, though -- I owe you a refill for that flask of yours, and a great deal more besides."

The End

Copyright 1998 by Rachel Howe

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