Thanks to the distorting echoes of the place, they could not be certain from which direction the noise had come. Rubber piping and cables hung from the ceiling of the tunnels here, like trailing tree roots piercing an animal's burrow or the mechanised intestines of some cybernetic sea monster.

"Come on," Ulysses said, "we're going to have to split up. It's the only way."

He turned and looked at the agitated faces around him.

"Cheng and Haugland, you go that way," he said, pointing to the tunnel left of where they had joined the junction. "Mr Wates, you take Swann and the good doctor that way," - he pointed right - "while Nimrod and myself will take this pa.s.sageway," he said, crossing the junction and continuing into the gloom ahead.

Within minutes, servant and master reached another junction within the maze of corridors. Lying on his side on the floor, cursing like a navvy, was Jonah Carcharodon, his wheelchair tipped over beside him.

"Carcharodon!" Ulysses exclaimed, coming to the aid of the invalid. "What happened to you?"

"d.a.m.ned if I know!" he snarled, verbally turning on his would-be rescuer.

"And where's Miss Celeste?"

"I refer you to my earlier answer."

As Ulysses and Nimrod righted the wheelchair and a.s.sisted Carcharodon back into it, the old man - who was obviously shaken, despite the show of bravado - began to prattle away, revealing what had happened prior to his little accident.

"Our party had split up to carry on searching this place. Celeste and myself were coming along this pa.s.sageway. McCormack was scouting ahead of us. I heard a cry from behind me, and as I struggled to turn round, to find out what was going on, some blighter - some b.a.s.t.a.r.d or other - tipped me out of my chair. Who would attack an old man, and an invalid at that? G.o.d knows where the others have got to."

"Or Miss Celeste," Ulysses said anxiously. "So where's McCormack now?"

"That b.a.s.t.a.r.d? He ran back on hearing Celeste cry out but ran straight past, leaving me like this."

"Which way?"

"That way," Carcharodon said, pointing along another tunnel leading off from the intersection.

His sixth sense screaming danger, Ulysses took off in the same direction, Nimrod close on his heels.

"But what about me?"

"Sorry, sir," Nimrod said with a slight nod of the head as he followed after.

Ulysses and his manservant rounded a bend in the corridor, Carcharodon's indignant shouts echoing back to them from the intersection, and pa.s.sed through another sealable bulkhead door into yet another chamber. His unconscious mind took in the fact that it was another laboratory of some kind, but his conscious mind was focused on the confused sounds of scurrying movement beyond. Slowing his steps he penetrated the half-lit gloom of the lab - pa.s.sing stacks of more stinking, gunk-filled fish tanks bearing faded and mildewed labels - until he caught sight of a pair of booted feet protruding from behind a tarnished metal gurney. Then, quickening his steps once more, he hastened round the end of the row, past the gurney, to see Captain McCormack lying on the floor of the laboratory, blinking as though in a daze, a hand to the back of his head.

"Quicksilver?" he slurred. "What's going on?" He brought his hand back round in front of his eyes. Ulysses could see that it was sticky with blood. "What happened to me?"

"You've been attacked," Ulysses stated, as the dazed captain seemed to be struggling with the realisation himself. "Where's Miss Celeste?"

"M-Mr Quicksilver? I-Is that you?" came a quavering fluty voice.

Ulysses immediately left the captain in Nimrod's more than capable hands and rushed around another stack of algae-streaked tanks to see Miss Celeste stumbling out of the shadows towards him. Her already dishevelled state was considerably worsened by the ugly bruise blossoming on her forehead and the trickle of blood dripping between the fingers of the hand she held to the injury.

"Miss Celeste," Ulysses said, unable to hide the concern in his voice as he hurried to her side. Putting one arm around her waist to support her, he encouraged her to sit down on the seat made by a fallen steel beam.

"Is everyone all right?" Wates asked, entering the lab, followed by Swann and Ogilvy, reluctantly pushing Carcharodon ahead of him.

"Captain McCormack and Miss Celeste have both been attacked," Nimrod stated bluntly.

"And me!" snapped Carcharodon, unhappy at not being the centre of attention. "I was attacked as well."

Ulysses shot the eccentric, self-obsessed billionaire a poisonous look but decided against saying anything.

"h.e.l.lo? What's going on? Everyone okay?" came Selby's voice as he entered the laboratory, followed by Cheng and Haugland.

Expressions of surprise and half-formed questions were all answered as Ulysses explained to everyone, once again, what had occurred.

"But who would do such a thing?" Haugland asked in disbelief.

"It must be someone who came on board with the rest of us," McCormack said. "Neptune didn't detect any human life-signs on the base before we all got here."

Eyes narrowed and immediately everyone present began reappraising their companions with suspicion.

"Then, if we are in danger, isn't it best we all stick together again from now on?" Ogilvy said.

"Well said, doctor," McCormack concurred. "Come on," he added, struggling to his feet, with Nimrod helping him, "this way."

"Captain, are you sure about this?" Ulysses warned. "Both you and Miss Celeste have suffered injuries and are doubtless also suffering from the effects of shock, isn't that right, Doctor?"

"Um, what? Oh, yes. Shock. Yes. Most definitely."

"The way I see it," McCormack said, wincing and putting his hand to the back of his head again as he attempted to stand upright, "we don't have any choice. If there's a madman on the loose, we need to hook up with the others and warn them."

The party moved on, as briskly as the injured amongst them would allow. Pa.s.sing another bulkhead door, Ulysses paused to look through the porthole at its centre to see what lay beyond. But all he saw through the thick, green-tinged gla.s.s was nothing but the broken sh.e.l.l of another dome and the open ocean beyond. Something had utterly destroyed that part of the facility which lay beyond the door. Suddenly a few inches of reinforced steel didn't seem like very much to be standing between them and the crushing expanse of the mighty Pacific.

Pa.s.sing into another corridor and from there through another bulkhead door, they entered the central chamber of the main biome - a waft of dry dusty air a.s.sailing their nostrils as they did so - only moments before what remained of the other party entered through an identical door on the opposite side of the room.

No pleasantries were exchanged, tired expressions and the briefest exchanges between the groups telling them what they already suspected: the base was deserted, whole swathes of it destroyed altogether. They had been able to find only a few usable medical supplies and a handful of tinned foodstuffs in a wrecked galley. And there was no sign of anyone having been left behind during whatever rushed evacuation had taken place.

Until now.

The explorers were all inextricably drawn towards the bizarre construction at the centre of the chamber, the grim memento of whatever had happened here exerting the pull of morbid fascination upon them.

They had to be in another laboratory. At its centre stood an amazing contraption, like a tiered dais, surrounded by banks of cogitator equipment and with the steel-cradle of a chair-harness at its peak. And strapped into the chair by a cracked leather harness was the body of a man.

It must have been sitting there for a long time in the one moisture-free room in the whole complex, for the body had become mummified naturally, cracked and peeling parchment-dry skin clinging to the angular bones. A curious device was strapped to the man's head. It looked like a metal-banded helmet. Various light-emitting diodes were arrayed upon its outer surface and a number of twisting cables trailed from electrode junctions on the top, connecting it to the chair and, by extension, the banks of machinery around it.

As to the purpose of such a device, Ulysses had no idea. As to how the mummified corpse had met its end, however, there seemed little doubt. The dead man had been shot, at close range. A clean bullet hole was preserved within the middle of his forehead, the results of the exit wound splattered across the back of the chair, eggsh.e.l.l shards of skull littering the dais beneath. The hollows of the dead man's eyes appeared to be staring at the small bubble of reinforced gla.s.s and steel at the apex of the dome, sightless sockets staring out at the miasmal abyss beyond.

"Oh my G.o.d," Crichton began, an expression of appalled horror on his face. He reached for his hip flask, to take another swig, only it wasn't there. He fumbled for it in his pocket, but it was gone, doubtless left somewhere as he and the rest of his party explored the facility.

Turning his attention from the macabre figure locked within the even more curious clinical chair-construct, Ulysses a.s.sessed the reaction of his fellow survivors.

To his mind there was something extreme about Crichton's meeting with the corpse. Surely he had witnessed much worse during their encounters with the Kraken and their flight from the Neptune? A nagging suspicion began to form at the back of his mind, struggling to take cohesive form.

All eyes were on the chair and the body bound within it. But where most gazed in morbid fascination or dumbfounded bewilderment, there was something else in the eyes of some of the more senior members of the party, specifically Carcharodon, Lady Denning, Major Horsley and of course Professor Crichton; something like recognition.

The only person not looking at the chair and its victim was Carcharodon's PA. Instead she had crouched down and was picking something up from the floor of the chamber, a floppy fabric thing, a child's crudely sewn rag-doll. Miss Celeste was turning the toy over in her hands in stunned silence.

"Oh, G.o.d forgive me," Crichton mumbled, his legs giving way, falling to his knees before the construction, unable to tear his eyes from the corpse bound within it.

"What is it, professor?" Ulysses challenged. "Do you know this man?"

"G.o.d forgive us all!" Crichton screamed.

"Do you know what happened here?" Captain McCormack uttered in startled surprise. "Is there something you're not telling us?"

"Major. Lady Denning," Ulysses tried. He couldn't quite believe what he was saying, even as he said it - how could it be possible after all? - but it seemed the only logical explanation. "Have you been here before?"

"Don't be ridiculous, man!" Carcharodon railed, turning on him again. "How could any of us have been here before? Quicksilver, you're a fool and a nincomp.o.o.p if you believe that. It's an utterly preposterous suggestion!"

But the professor remained on his knees, tears splashing onto the metal plates before him, making tiny mortar-blasts in the dry, dead dust.

A scream rang out through the open door by which the rest of the party had entered the laboratory chamber, that sent a shiver of fear and excitement through Ulysses' body.

"Constance!" he exclaimed, already moving. "But of course, they were still left behind. The only safety here is safety in numbers."

"The attacker!" another voice added.

Faltering steps became great bounding strides as Ulysses ran from the chamber. Others joined him in pursuit, a cacophony of clanging footfalls rebounding from the steel-plated tunnel walls. And the screams kept coming.

Ulysses was the first to enter the dive chamber, joined soon after by Nimrod, Captain McCormack, Cheng, Swann and Clements. He stumbled to a halt in appalled horror as he took in the scene before him.

Constance was standing only a few feet from a secured airlock door, her hands to her face, screaming in abject horror. John Schafer beat at the door with his fists, bellowing in anger as he tried to open it again. On the other side of the gla.s.s the face of Miss Birkin filled the porthole, locked into an expression of unutterable terror.

Ulysses rushed to his young friend's side, Nimrod following in his stead, all three of them attempting to force the door as a dull, droning siren began to blare from speakers somewhere within the chamber.

"It's no good!" shouted Selby.

"What do you mean?" Ulysses asked, voice tensing as he strained to get a purchase on the rim of the airlock hatch with his fingers and somehow prise it open.

"You're wasting your time," the Neptune's chief engineer said coldly. "Once an airlock's activated, the fail-safes make sure that the protocols cannot be overridden."

"What? It's been activated?" Ulysses turned his attention back to the door and the terrified old woman trapped in the airlock, her face bathed in the pulsing orange glow of an amber warning lamp.

As if to confirm Selby's words, beyond the unnervingly silent Miss Birkin, the outer door of the airlock ratcheted open.

There was nothing any of them could do as the sea flooded into the chamber, filling it in seconds, crushing the old woman to a pulp before she had a chance to drown.

As the messy remains of what was left of Constance's aunt were drawn out of the airlock in a swirl of ocean current, a terrible realisation crept over Ulysses.

Glenda's murderer had come with them. Someone, hiding in plain sight in the party of survivors within the Marianas Base, was the killer and had dared to strike again, even given the hopelessness of their position, surely realising that there could be no escape for them either now.

What had seemed to be their sanctuary from all the horrors that the abyssal depths held for them, had now become their prison.

CHAPTER EIGHTEEN.

The Accused "We only left her alone for a moment," John Schafer was saying, "a minute or two at most."

The young man looked completely wrung out as he tried to make sense of what had just happened. The stress of the situation, having personally taken responsibility for the safety of his fiancee and her aunt, had begun to get to him like never before. And this feeling was only made worse by the fact that one of his charges was now dead, and having suffered such a horrible death.

Constance Pennyroyal was slumped on the floor against the airlock door, sobbing into her hands. At least her anguished cries of grief had subsided for the time being, but, to Ulysses' mind, the heart-rending stifled sobs seemed almost harder to bear.

"We heard something - a crash, a cry - and went to see what was going on," Schafer went on. "We only left her alone for a moment."

"It's the killer," the purser said darkly. "Whoever killed Miss Finch is with us, here, in the base, hiding somewhere amongst us."

"A stowaway, you mean?" Lady Denning asked.

"You can tell yourself that, if you like," Selby said, "but there was no one on board before any of us boarded back at the sub-dock on the Neptune."

"How can you be sure?"

"You'll have to trust us on that one, your ladyship."

"Trust you? But someone amongst our party is a killer! How can we trust anyone anymore?" She took in the faces around her one at a time, alighting on Major Horsley's bristled red-veined face. "Even those people we thought we knew."

"The killer's here?" Dr Ogilvy repeated, as if struggling to comprehend what he was hearing. "But if that's the case, we're all doomed!" He seemed to be paying particular attention to Harry Cheng as he had his say.

"We're not done yet," Ulysses said, one eyebrow arching and the corner of his mouth following suit, a wry smile beginning to form on his face. "It's quite simple, really. As it stands none of us are going to get out of here alive if we don't keep to the plan. The killer hasn't shown themselves to be suicidal, otherwise we wouldn't be in this position now."

"How can you be so calm and detached about all this?" Schafer asked, as if he was revolted by Ulysses' lack of demonstrable emotion. "Especially after what happened to Glenda."

Ulysses fixed the younger man with a hard stare. "Whatever it takes to get through this," he said coldly. "Anyway, as I was saying, the killer could have put an end to all of us any number of times, if they hadn't valued their own life. No, there's a purpose to these killings and as long as we stick together, and stick to the plan, there's nothing our mystery killer can do to harm us. Isn't that right, Captain?" Ulysses asked directing a wicked grin at McCormack, his ally in all their plotting so far.

"Mr Wates, seize this man," the captain said, pointing an accusing finger at Ulysses.

"Captain?"

"McCormack?" Ulysses said, in disbelief, his nascent smile being replaced by a knot of confusion.

"I said, lay hands on Mr Quicksilver!"

"You cannot be serious," Ulysses pressed on, incredulous. "That blow to the head must have been worse than we first thought."

Just as confused as Ulysses, but with years behind him as a devoted naval officer, Wates moved forwards, almost as if reacting by instinct upon hearing his captain's command, and put a cautious hand on the dandy's arm. All the while he kept looking to his superior for affirmation of his actions.

In response, Nimrod moved to stop Wates.