"Now that you mention it, yes, I do see a resemblance. Your father was Felix Lamprey."

"Little Marie Lamprey?" Carcharodon uttered in disbelief.

"Yes, you doddering old fool." She hissed. "All this time, right under your nose. And you never knew. And not so little now, nor so helpless! The cuckoo in the nest."

"More like the viper in the nest," Ulysses said quietly to himself.

"Well, I..." Carcharodon bl.u.s.tered.

"What? a.s.sumed that I was dead like my father, left behind for the sea to claim? Didn't give me a second thought? Never wondered what happened to that little girl you all left behind? Didn't care what had happened to her? Is that what you're trying to say?"

Ulysses had never heard the young woman say so much during all time they had spent together.

"It all makes sense now," Ulysses said.

"Oh, does it?" she snapped. "I'm so pleased. It took you long enough though, didn't it, Mr Consulting Detective? Had to see it for yourself before you would readily believe it, didn't you? We had to show him, didn't we, Madeleine?" The doll said nothing. "Well perhaps you can explain how I can make sense of it all, tell me why they killed my father and left an innocent little girl behind to die, a sacrifice to the beast, just like my mother, because I don't understand it!"

Ulysses stared deep into her eyes. If the eyes were the windows to the soul, then the soul he could see reflected in these particular orbs was a damaged, tarnished thing. She was wild now, any semblance of the mousey deference she had managed to maintain for so long entirely gone. They were now seeing her true face. The quiet, patient, ever-tolerant, uncomplaining, subservient Miss Celeste had vanished, to be replaced by the wrathful, vengeful, violent and unpredictable Marie Lamprey. And where Miss Celeste had seemed like a perfectly rational and reasonable individual, her alter ego was utterly mad.

The slightest of movements distracted Ulysses for a split second. In that moment his eyes jerked a fraction of an inch, and refocused on the figure of Selby, but only for a moment. But that was all it took for Ulysses to inadvertently betray the engineer.

Marie Lamprey, her own psychotic stare transfixing Ulysses' eyes, as much as his were locked on hers, saw the miniscule change.

She spun round as Selby heroically moved to stop her. There was the concussive retort of a pistol firing and a spray of red, grey and white splashed the viewing port beyond the pilot's position, as a soup of blood, brains and skull plastered the inside of the reinforced c.o.c.kpit. Selby collapsed, looking like a puppet that had had its strings cut.

Constance gave a m.u.f.fled scream from behind her gag and even Ulysses, who had seen far too much mindless violence in his life, gave an involuntary cry of shock. But despite that, the second Marie Lamprey moved against Selby, Ulysses took a long step forward in the ma.s.sive suit.

And then the gun was back on him.

"Don't come another step closer," the insane young woman warned him, "or you know what I'll do."

"That? Against that suit of armour?" Carcharodon pooh-poohed, unable to stop himself, having got away with treating people like inferior beings all his life. "Don't be ridic -"

Carcharodon was silenced by Marie bringing the b.u.t.t of the gun down hard on the back of his head. The old man gasped in pain, his head dropping onto his chest.

"Shut up, you senile imbecile!" she snapped. "I mean it, I'll start the countdown on that bomb you're wearing. And once it's started, there's no stopping it."

"Why?" Carcharodon slurred, unable to take in everything that had happened in so short a s.p.a.ce of time, desperate for some reason to be given to rationalise the irrational.

"Why?" she shrieked. "You want to know why? After all this time, only now do you wonder why all this had to happen? Why you all had to die? Isn't it obvious?"

"Revenge," Ulysses stated bluntly, "pure and simple. It usually is."

"And what's that supposed to mean?" Marie railed, turning on Ulysses. "Don't think for one second that there was anything usual about what happened. Everything happened for a reason, the most important reason of all: for my father's good name! I couldn't have him remembered as a psychopath or worse, forgotten about!"

"Oh no, I can see that. The name of Lamprey is going to be remembered for a very long time," Ulysses said. "You've certainly made sure of that. You'll be infamous after what you've done, but it still won't be your father that people remember, not when the name of Marie Lamprey is plastered across the headlines of broadsheets across the Empire."

"Why, you!" she spluttered, reaching for the timer dial on the hastily-constructed device.

"I understand why you believed Carcharodon here, Lady Denning, the Major and Professor Crichton had to die," he went on. Marie's hand froze, hovering over the dial.

"You do?" Carcharodon bristled.

"The Professor practically gave the game away himself. He actually told us what your motivation for committing this series of cold-blooded crimes was. You wanted revenge on all those you saw as being responsible for your father's death, for driving him to do what he did, once they had turned their backs on him. The other leading figures of the Leviathan project. You even planned to ensnare Josiah Umbridge, the industrialist, in your little trap; only he didn't take the bait. He sent that wretch Sylvester in his stead.

"And it was thanks to you that all the right people just happened to be on board ship for the Neptune's maiden voyage, wasn't it?"

Marie Lamprey said nothing but continued to fix Ulysses with her disturbing wild-eyed stare.

"Your own employer's confession should have given you away long ago."

"What confession?" Carcharodon groused, one hand clamped to the rising b.u.mp on the back of his head.

"It was over dinner, that first time at the captain's table. You said yourself, Jonah, it hadn't been down to you that any of us had been invited on board for the inaugural round-the-world cruise. You told me that your PA had sent out all the personal invitations. You said that she did everything for you. That way she could make sure that she had everybody here who she needed, or at least that's what you had hoped for," he said, turning back to Marie. "But as we've already established, Umbridge escaped the end you doubtless had cooked up for him, by dint of being at death's door already and being too unwell to travel.

"You must have been plotting this for years," Ulysses went on, only now, as he reasoned through all the salient points, realising the scale of Miss Celeste's - or rather Marie Lamprey's - audaciously planned act of vengeance. "What probably started out as a backlash against the injustice of a world that had taken both your parents from you, fuelled by grief and a dozen other childish insecurities gradually - perhaps inevitably - became an obsession until the desire for revenge was your whole raison d'etre. There was nothing left but the desire to be revenged on those you saw as being responsible for Felix Lamprey's death. Quite simply, your obsession drove you mad.

"It must have taken you years to work yourself into a position from where you could put your plan into action, to satisfy your sick irrational need for retribution."

"Don't say that!" Marie screeched.

"What? That you're sick, Marie?" Ulysses reasoned calmly. "But it's the truth. You are: terribly sick."

"They were the ones who were sick, weren't they, Madeleine," she sobbed, tears suddenly streaming down her face, "leaving a child to die having already done away with her father?"

"Ruthless, yes, but sick? I would like to be able to agree with you, but I'm not so sure. Whereas you, my dear, are one hundred per cent certifiably a fruitcake!"

"Stop it!" she screamed. "Stop saying that!" She pushed the muzzle of the gun hard against Carcharodon's head.

"So I suppose it was you who sabotaged the ship as well," Ulysses went on, managing to stay sounding calm, although he didn't feel in anyway calm on the inside. "But how did you manage that, I wonder?"

"You mean you haven't worked that out yet?"

"I thought I had," Ulysses confessed. "But I'm afraid I had this wretch Carcharodon here down as the culprit of our little morality play."

Carcharodon looked up at Ulysses, indignation blazing in his bleary unfocused eyes.

"I saw the log," Ulysses explained. "I know that the person who initiated the sabotage routine buried within the AI's memory core used the ident 'Father' to access the system, and I'm afraid I took that to be you, Jonah. I thought it was an insurance job." He paused as realisation struck. "Oh, yes. Oh, of course. If only I had seen it before. Lady Denning told us all we needed to know about the ident.i.ty of the one the AI referred to as 'Father'."

"Then I take it I'm exonerated, cleared of all charges?" Carcharodon asked. "For all the good it will do me."

"Lady Denning told us that Lamprey - Felix Lamprey I mean - designed the difference engines that maintained the life support systems for Marianas Base. She also said that these more rudimentary systems were the forerunners of the significantly more complex artificial intelligence created for the Neptune. Its father, as far as the AI was concerned, wasn't you, Carcharodon, but Lamprey, the creator of the original AI template. Oh yes, very clever."

Still the quivering woman returned his stare, fire in her eyes, like the h.e.l.lfire surely crisping her soul even now, in light of what she had done.

"And I'm guessing you used a combination of your cogitator skills and the privileged information you had access to as Carcharodon's personal a.s.sistant to sneak into the AI chamber at a time that suited you, access Neptune and activate the programme you must have implanted inside its memory core probably months before."

"Very good, Mr Quicksilver. He thinks he's so clever, doesn't he, Madeleine? But it doesn't matter now, does it? He's still too late to stop us, isn't he?"

"All right Miss Celeste, or Miss Lamprey, or however it is you like to be known nowadays, I understand why, by your twisted logic, Carcharodon and all his cronies from Project Leviathan were doomed to die. But tell me, why did the others have to die? Why did you kill Glenda Finch?

"Even now, after all we've shown him, all we've told him, he can't see it, can he, Madeleine?"

The tenuous grasp Marie Lamprey had on reality was steadily slipping away.

"No, wait, I see now. I've just given you the reason myself, haven't I? The AI chamber. You planned to set your scheme in motion almost twenty-four hours earlier, that night after the Blackjack marathon at the Casino. But on that occasion you were seen, or at least you thought you were. Of course. Being so bound up in your own scheme, with your own psychotic need for revenge, you were always paranoid about anyone else finding out what you were up to and putting a stop to things before you were done. You must have met Glenda as she was leaving the AI, after she had been doing a little digging of her own into the Carcharodon's finances. And you couldn't risk arousing her suspicions about you as well, could you?"

"Everything had been worked out down to the finest detail. I couldn't let a snooping strumpet like her ruin everything for me before I had even begun."

"But you didn't stop there, did you? You couldn't, not after Miss Birkin revealed that she'd seen the murderer with Glenda, the poor old biddy. What was it the Major said about her? Oh yes, always looking for a conspiracy behind everything. If only she'd known. If only she'd kept her mouth shut!

"Only she hadn't seen you at all, had she? She saw me, escorting Glenda back to my room after the Blackjack game. She didn't need to die, not even by the standards of your twisted logic. And of course, having killed Miss Birkin you had to keep on eliminating all of those who might have overheard her conversation with the captain.

"She wasn't a threat to you, but then you couldn't have known that until later, after Captain McCormack accused me of your crimes! And while people were busy thinking it was me, and added to that when Cheng tried to carry out his ill-timed little coup, it gave you all the distraction you needed to keep killing, hunting down the doomed members of Project Leviathan one by one, making sure they all paid for what they had done to your father. What they had done to you. You even bought yourself some more time by faking that attack on Carcharodon and yourself, when your attack on the Captain failed.

"And each of them died in a manner befitting the part they played in the creation of the Kraken. Horsley the big game hunter, skewered like a shish kebab by a harpoon, Crichton the evolutionary biologist poisoned with a lethally evolved neuro-toxin, Denning the marine biologist, electrocuted with a prototype cybernetic tentacle that she had helped to create. And now you've turned Carcharodon into some kind of living bomb.

"So, what I'm thinking now, having reached something of an impa.s.se, is - where do we go from here?"

"We're not going anywhere," Marie Lamprey said coldly.

Reaching behind her with her free hand, she lifted something from the control console, something Ulysses had failed to notice, so preoccupied had he been with the goings on between Marie, Carcharodon and himself, although he realised now that he had seen it before - they all had, only the last time it was being worn by a dead man.

Carefully, Marie placed the metal-banded helmet on top of her head. The coloured light-emitting diodes that covered its surface were blinking on and off like fairy lights. The wires that trailed from the crown had been bound together into one thick cable which, in turn, had been plugged into the console.

"You were busy while I was away, weren't you? Well, they do say the Devil makes work for idle hands."

Marie said nothing, but continued to press the barrel of her gun roughly against her employer's temple, staring ahead of her at Ulysses. There was something about the look in her eyes that suggested she was seeing something else, that wasn't there with them inside the submersible.

"I'm guessing you're as much a whiz with computers as your father was. It looks like you've also inherited his tendency towards mental instability," Ulysses added. "But what, precisely, are you planning on doing with that, Marie?"

A slow smile spread across the haggard young woman's lips, and at that moment it scared Ulysses far more than the gaping grin of the Megalodon that had tried to make a meal of him.

"Why, don't you know? This is how I'm going break this stalemate we've got ourselves into. This is how I finally put paid to the last of the masterminds behind Project Leviathan, behind my father's murder, and the son of the government representative who allowed such a scheme to continue. All in one easy stroke."

Knowing he had nothing to lose by doing so, Ulysses turned and peered out through the viewing port at the rear of the cabin.

There was something moving out there in the night-blue darkness.

The cold chill of fear slithered down his spine and made itself at home in his gut, turning his bowels to ice water.

He had hoped against hope that they had seen the last of it, that it had been destroyed along with Marianas Base. But deep down he always knew that such a result would simply be too good to be true.

He could see it more clearly now as it slid through the water after the two craft, chasing them to the surface, its grasping arms reaching out ahead of it.

And now Ulysses could see the injuries it had sustained, the damage it had suffered, caught up in the death throes of the dying facility. It had lost parts of several of its arms, sheared metal showing amidst the torn flesh. There were also whole areas where its pallid underbelly, and even pieces of its armoured sh.e.l.l, had been torn asunder to reveal its endo-skeleton beneath. And yet, despite having suffered such extensive damage, the Kraken still looked more than capable of taking down both the Ahab and the Nemo.

Ulysses turned back to face Marie. She looked very peculiar with the bulbous metal helmet covering her head down to her eyes, almost comical.

"I was wrong in my a.s.sumptions about the value the killer placed on their own life."

"What do you mean?" Marie asked, Ulysses having got her attention, piquing her own sense of the curious.

"You would willingly sacrifice yourself to see us all dead."

"With my father's killers brought to justice, my life has no further purpose. This has been my life's work. With it completed, there is no reason for me to keep on living."

"Why? Why? Why?"

Ulysses was slightly surprised when he realised that Carcharodon was sobbing as he repeated the same word over and over through his tears. The man who he had known to show hardly any emotion, other than anger or annoyance, was crying like a baby.

"What do you mean, why?" Marie shrieked, lifting the gun from the old man's head only to bring it down hard again against his skull a second time. "Haven't you been listening? He never listens, does he, Madeleine?" She was screaming now, her words a screeching banshee wail. "Don't you understand? You have to understand why you have to die! He has to, doesn't he, Madeleine, otherwise it's all been for nothing." Tears were streaming down her face again, mucus running from her nose.

"I understand. I understand why I have to die," Carcharodon struggled on, gasping for breath from the pain of the blows to his head. "I drove you to this. I understand that. But why did the others have to die?"

Now it was Marie Lamprey's who suddenly didn't understand. "What?" she said, her voice suddenly quiet. Ulysses thought he preferred it when she had been screaming.

"It was me. It was me who killed your father."

"What?"

"It was me. I shot him."

Marie's attention was now fully on the old man, slumped forward in his wheelchair at her side. He suddenly looked so very small and frail as he quietly confessed his sins, the two of them, employer and psychotic employee, master and servant, frozen in that moment of time in some weird parody of priestly absolution.

Ulysses readied himself. He could feel the moment coming when he would be able to bring this matter to its resolution.

"You killed my father?" Marie stammered, suddenly the uncertain, insecure Miss Celeste surfacing again.

"Yes. And there is another crime of which I am guilty. In doing so I helped create another monster, and this time I'm going to face up to my responsibilities and do away with it!"

With that, Carcharodon flicked the switch on top of the timer in his lap.

With a whirring hum the hand began to turn, the needle on the dial hastening away the seconds until the moment when the bomb would detonate.

"What have you done?" Marie screamed levelling the gun at Carcharodon again, holding the weapon tightly with both shaking hands.

The old man looked her straight in the eye and said with chilling calmness, "I'm bringing an end to this impa.s.se."

The woman pulled the trigger. Ulysses heard the sharp crack of the gunshot even as he saw Jonah Carcharodon's head disintegrate in a spray of blood and bone.

It was now or never. Ulysses took a bounding step forwards. Still screaming, Marie grabbed Carcharodon's wheelchair by its handles and pushed it into his path, the old man's body lolling forwards as she did so.

Catching the chair in the huge gauntlet fist and the pincer-claw, Ulysses pushed back. Caught between the arms of the chair, Marie Lamprey stumbled backwards, the helmet falling from her head. Unbalanced she fell against the chair, skewing it sideways, before she toppled over, falling into the still open airlock.

The timer continued to spin round, speeding towards inescapable oblivion. Ulysses could still hear it over the m.u.f.fled screams of the bound Constance Pennyroyal.

Without a second thought, Ulysses pushed the dead Carcharodon, in his invalid's chair, in after Marie and punched the control panel beside the airlock. With a satisfying shunk, and the hiss of altering air pressures, the inner door shut. Sirens sounded. Lights flashed. Marie Lamprey's face screamed at Ulysses through the small window in the airlock door. But there was nothing that could be done, not now.