"I see no point arguing on a subject upon which, by all scientific measurements of the time, we cannot gather any data that might give us an answer," I replied.

"We cannot measure gravity, not in any practicable sense," retorted Vincent, his face settling into something of a sulk. "We cannot say how fast it is, or even what it is, yet you believe in it as much as-"

"Through observable effect."

"So you limit our debates based on the tools available?"

"A scientific argument must have some degree of data, some... some sniff of theoretical basis behind it; otherwise it's not a scientific argument, it's a philosophical debate," I replied, "and therefore hardly my department."

Vincent gripped the arms of his seat, as if only that solid presence would prevent him springing up in rage. I waited for the tantrum to pass, "A thought experiment," he said at last. "You will at least tolerate that?"

I gestured vaguely over the lip of my glass that, just this once, I might be open to the idea.

"A tool," said Vincent at last, "for the observation of everything."

I waited.

There seemed nothing more.

"Well?" I asked at last. "I'm waiting for the development of the argument."

"We accept the existence of gravity not because we can see it, or touch it, or say with any great certainty what it is, but because it has observable consequences which can be predicted through consistent theoretical models, yes?"

"Yesss..." I concurred, waiting for the snag.

"From observable effects, we deduce non-observable consequences. We observe that an apple falls and say, 'It must be gravity.' We watch the refraction of light through a prism and declare it must be a waveaand from that deduction more deductions follow on behaviour and effect, amplitude and energy. So, by very little effort you can quickly theorise your way to the very bottom of things based on rather crude observable effect, as long as it fits the theory, yes?"

"If you're about to propose a better method than the scientific one...?"

He shook his head. "A tool," he repeated firmly, "that can deduce... everything. If we take a building block of the universe, the atom, say, and announce that it has certain observable effectsagravity, electromagnetism, weak nuclear, strong nuclear forcesaand proclaim these to be the four binding forces of the universe, then, if this is so, should it not be theoretically possible to extrapolate from this one tiny object, within which the very basis of everything is contained, the entire functioning of creation?"

"I can't help but feel we're straying back into God's territory," I reminded him.

"What is science for, if not omnipotence?"

"Are you looking for an ethical answer, or an economic one?"

"Harry!" he blurted, jumping back to his feet and pacing the slim area of floor I'd carefully cleared some months ago for just this purpose. "Always you dodge the question! Why are you so afraid of these ideas?"

I sat up a little straighter in my chair, his indignation reaching almost unusual levels. There was something odd in what he was saying, a little warning at the back of my mind which slowed my speech, made me answer with more care than usual. "Define 'everything'," I said finally. "I assume that your... tool, if you like, your hypothetical, impossible tool, will, by deducing the state of all matter in the universe, be deducing both past and future states as well?"

"It would stand to reason, yes!"

"Allowing you to see everything that is, and everything that was, and everything that will be?"

"If time is considered to be non-absolute, then yes, again, I think that's reasonable."

I raised my hands, placating, thinking it through slowly. Alarm was growing at the back of my mind, seeping into my throat, trying to get past my tongue, which I moved so carefully. "But by the very act of observing the future, you yourself change it. And so we're back with our time traveller who stepped from his machine and saw the past. You, in seeing the future, will model your behaviour differently or, if not that, the future will be entirely tempered by the single moment in which you came to know it, altered by the act of being observed, and we return again to a paradox, to a universe that cannot be sustained, and even if that were not enough, surely we must ask ourselves what will be done with this knowledge? What will men do when they can see like gods, and what... and..."

I put my whisky glass down to the side. Vincent was standing still in the middle of the floor, his back half-turned to me, fingers splayed at his side, body stiff and straight.

"And," I murmured gently, "even if we were not worried about men obtaining godhood, I would raise this concernathat the strong nuclear force upon which your hypothesis depends won't be posited for another thirty years."

Silence.

I rose from my chair, frightened now by Vincent's stillness, by the muscles bunching along his back and shoulder, locked tight.

"Quarks," I said.

No reaction.

"The Higgs boson, dark matter, Apollo Eleven!"

Nothing.

"Vincent," I breathed gently, reaching out for his shoulder, "I want to help."

He jerked at my touch, and I think we both felt a rush of fight-or-flight adrenaline in our systems. Then he seemed to relax a little, head turning down, and smiled a distant smile at the floor, half-nodding in recognition at a thought unseen. "I wondered," he said at last, "but hoped you weren't." He turned sharply, swiftly, staring me straight in the eye. "Are you one of them?" he demanded. "Are you Cronus Club?"

"You know about the Cronus Club?"

"Yes, I know about it."

"Why didn't you-"

"Are you? For God's sake just answer me, Harry."

"I'm a member," I began to stammer. "Y-yes, of course, but that doesn't-"

He hit me.

I think I was more surprised than genuinely hurt. I'd encountered violence and pain, of course, but in this life I'd had such a comfortable existence I'd almost forgetten the feeling. If I'd been braced, I might have stayed standing, but shock more than anything else knocked me back into a pile of books. I was aware of the taste of blood in my mouth and a tooth wobbling at the touch of my tongue which had not wobbled before. I looked up into Vincent's face and saw coldness mingled with maybeaunless my mind imagined itamaybe a shimmer of regret.

Then he swung his fist once more, and this time surprise didn't have time to get a look-in.

Chapter 29.

"I hate to be the one to ask this," she said. "But if the world is ending, what are we really expected to do about it?"

Twelfth life.

Aged six, I wrote a letter to the London branch of the Cronus Club, requesting enough money to get me to London and a standard Club letter inviting me to join a prestigious school. The money was left in a dead letter drop, at my request, in a village called Hoxley, where some many lives ago I had fled from Phearson by the light of the moon.

I wrote a letter to Patrick and the dying Harriet, wishing them the best and thanking them for their time, and set out. In Hoxley I collected the money from its stash in a tin box beneath a hazel tree, and bought myself a fare to London. The baker smiled at me as he passed by in the street, and I felt Phearson in my belly, heard his footstep in my ear, and held on to the wall, wondering why my body refused to forget a thing which my mind had long since passed on by.

I took a cart to Newcastle, and when the ticket inspector on the train asked me if I was accompanied, I showed him the letter inviting me to attend a school and told him my aunty was waiting at London.

My aunty for the purposes of this life's adventure was Charity Hazelmere.

"There's the boy!" she hollered brightly as the conductor escorted me carefully from the train. "Harry, come along at once!"

There are many ways a child may be lifted from his linear parents. The dead letter drop I have referred to, along with the payment of suitable monies and provision of suitable documents, is a generally accepted and popular one. It provides enough resources for the kalachakra to make his own way to the nearest Cronus Club without necessarily exposing vital information such as where the kalachakra lives and is raised. It does, however, provide a degree of exposure in that it can narrow a search to an area. A generally more established rule is for a dead letter drop to be placed in a region where the recipient knows his parents are likely to take him at some point in the early years of his life, thus securing supplies and discretion in one swoop. The only danger of such an arrangement of course being the unlikely event that the family does not conform to expectations.

If discretion is not a concernaand arguably why should it be for the most affable and innocent of our kinathen direct intervention is also sanctioned, and no one did direct intervention quite like Charity Hazelmere. With her patrician nose, operatic voice and collection of stiff black bodices, which I have never seen her vary in all her lives, she is every adult's nightmare of a fiend headmistress, her merest glance over the half-moon spectacles slung by a chain and balanced on the end of her nose enough to reduce mere mortals to quivering doubts and fear. She has cajoled, bullied, badgered, hounded and occasionally plain kidnapped kalachakra children from their trembling parents, all in the name of a quieter life for her charges and with the express hope that in years to come other kalachakra will have the good sense to do the same for future members of our kin.

For all this, her views are arguably rather parochial.

"It's all very well to ask us to get involved," she exclaimed. "But how?"

Twelfth life.

It's rare to see a gathering of the Cronus Club. Members drift in and out all the time, but a full regional assemblyainvitees summoned by cards with gold trim, agenda: the end of the worldais a sight to see. At six years old I was the youngest. At eighty-two, Wilbur Mawn was the oldest. As a child Wilbur had met the Duke of Wellington, and when growing up as a young man in London he had swapped cards with men who had fought for, and against, revolution in France. Now he was to be our next messenger, a man shortly due to die, who could, by his death, bring the message back to 1844athe world is ending and we don't know why. So what are you going to do about it?

"Nothing!" declared Philip Hopper, son of a Devon farmer with a taste for adventure that had led him to die in the Second World War six times, the Korean War twice, and Vietnam once, as a rather decrepit war correspondent no army would employ. "The factors are too many, the information too vague! We either need more information or nothing at all, since we can't begin to determine what's at work here."

"I think," suggested Anya, a White Russian refugee who tended to abandon the White Russian cause for a more comfortable life abroad in 1904 with a sigh of inevitability, "the issue concerns the speeding-up. The end of the world is speeding upait is happening earlier in every life. That implies that the cause is changing, and what, we must ask, is the cause of change?"

Eyes turned to me. I was both messenger boy and, by dint of being the youngest, the most widely assumed to be in touch with modern scientific reasoning on the subject, if you considered the 1990s to be modern.

"In every life we lead, regardless of every death we pass," I said, "the world around us is unchanged. There is always rebellion in 1917; there is always war in 1939; Kennedy will always be shot and trains will always be late. These are linear events which do not vary, as far as we can observe, from life to life. The only variable factors are us. If the world is changing, we are the ones who change it."

"Against the rules of the Cronus Club!" interrupted Charity furiously, never one to be distracted by the bigger picture.

"The question therefore becomes," I went on, legs dangling from the chair on which I was perched, "not why is the world ending. But who?"

Chapter 30.

Killing an ouroboran is hard, but I would argue that killing a linear mortal can often be harder, for you cannot simply prevent their birth in one life and have that serve as death for all. Each murder must be conducted each life, a matter as routine as brushing teeth or trimming nails. The key is consistency.

It was 1951 and I was living in London.

Her name was Rosemary Dawsett: she was twenty-one years old and liked money. I was lonely and liked her. I won't pretend it was a profound relationship, but it was, in its own way, reasonably honest. I didn't ask for exclusivity, and she didn't attempt to extort, though she could see that I was a reasonably wealthy gentleman. Then one day she missed our meeting, and I went to her lodging and found her, in the bath, wrists slashed. The police called it suicide, dismissing her as one more dead tart, but I looked and I saw. The blade had gone too deep into her right wrist, slashing the tendons; she couldn't have been strong enough to hold it for the next cut on her left, and besides there were no hesitation marks, no signs of doubt, no note, no shuffling around as she tried to get the angle right or worked up her courage. As someone practised in the art of self-destruction, I knew a murder when I saw it.

The police refused to investigate, so I took over. The evidence was sickeningly clear to find, once you looked. Fingerprints, one even in the blood itself, and the madame downstairs had a list of all Rosemary's regulars and thought she had seen one Richard Lisle leaving as she had come home. Getting his address was a matter of a few polite phone calls, getting his fingerprints was a case of approaching him in a pub, buying him several pints and listening to his ramblings, which ranged from a discussion of fine art taken from a textbook to loud and raucously cheered remarks about the bloody Pakis and wogs. His voice was the overly slippery upper-class accent of a middle-class man with aspirations and elocution lessons. In thirty years it would be a parody accent, used by comics to expose the sad cliche of the lonely man who believed that Ascot was sacred and could never quite get a ticket. In a merciful mood I might have felt sorry for this little man, striving to be accepted by a portion of society that didn't just ignore him, it didn't even notice him knocking. Then I took his beer glass home and checked his prints, which matched the print in the blood on the side of the bath, and any sympathy I might have felt was gone.

I sent my evidenceabeer glass, analysis of the blood patterns, the fingerprint in the bloodato Scotland Yard, to a detective called Cutter who had a reputation for imagination and prudence. He interviewed Lisle two days later, and that, from what I could tell, was the end of it. Two days after that another prostitute hanged herself, and there were self-defence marks on her wrists and arms, chloral hydrate in her bloodstream. This time, though, warned by the visit from the police, Lisle had been careful and left not a fingerprint behind.

I had not committed murder at the time, although I had killed. By this point I knew of seven men I had killed directly, six of them in the Second World War and one in self-defence. I also calculated that I had contributed to the deaths of many hundreds more, through acts as banal as fixing the wheel on a B-52 or proposing a more reliable timer which could later be used on a bomb. I considered whether I had the courage to commit actual, cold-blooded murder, and concluded with mild regret that I did. I informed myself that I had the decency to be ashamed, but what little comfort that was compared to the certainty that I would commit this act. I would kill Richard Lisle.

I prepared carefully. I bought a boat under an assumed name for cash in hand, a crabby tin thing with a lower deck that stank of the slick white fungus which infested its walls. I bought petrol and food, hydrochloric acid and a hacksaw, careful to spread my purchases over as wide an area as possible. I bought gloves and rubber overalls, examined the tides on the Thames and observed the traffic in the night. I acquired several ccs of benzodiazepine and rented a room opposite the pub where I had first acquired Richard Lisle's fingerprints. I waited until one nightaa Tuesday, the smog thick green over the streetsawhen he came to have a drink, and went in. I joined him, remembering our old acquaintance and asking how he had been. He was gleeful, happy, a gleam of sweat about his face and a loudness in his speech that at once set alarm bells ringing in my mind. What had he done to induce such delight? I examined him, every part, for a sign of something amiss, and smelled the fresh soap in his hair, saw how scrubbed his nails were, how fresh and clean his clothes were despite the settling lateness of the hour, and knew with that irrational part of the mind that rationality always denies that I had come to him a few hours too late. Rage flared up inside me and briefly my plan was forgotten, my efficient, organised scheme. I still smiled, and smiled, and we staggered out together into the coal-hung air at closing time, hanging off each other, best of friends, our skin smeared black by the air we breathed. But as we staggered away up the street, one of those lingering terraced streets of tiny houses that still hid beneath the craters of the East End, he looked up at the sky and laughed, and I punched him and punched him again, and when he fell I straddled him, grabbing him by the throat and screamed, "Where is she? Who was it this time?" and punched him again.

In the rush of adrenaline, in my rage, smothered by the smog and hidden by the dark, all my plans, my careful, reasoned plans were forgotten. I barely felt the shock against my knuckles as I drove my fists into his skull. Nor did I register the flick knife that he drove up through my abdomen and into the bottom of my left lung until, drawing breath for another strike, I realised I had no breath to draw. His face was jelly but I was dead. He pushed me off him and and I fell like soggy pudding into the gutter, the dirty water flecking my face. He crawled over to me, his breath wheezing, blood popping and bubbling out of the end of his shattered nose. Awareness of the knife in his hand gave me an awareness of what he did with it, so I felt the next three strokes as he drove it into my chest. Then I felt nothing at all.

Chapter 31.

Many, many lives later, I sat down opposite Virginia in the lounge of the Cronus Club and said, "His name is Vincent."

"Darling, that's hardly much to go by."

"He's one of us. Ouroboran. I asked him about the Cronus Club, and he attacked me and walked away."

"How immature of him."

"He has ambitions."

Virginia was more than capable of being uninterested when she wanted to be. She wanted to be now. She stared at the ceiling as if it was the most fascinating thing in the world and waited for the rest.

"The message keeps coming down to us from the future generationsathe world is ending, the world is ending. Nothing changes about the established course of linear eventsanothingaexcept us."

"You suggest this... Vincent... may be the 'who' which leads to the 'what'?"

"I... no. I don't know. I'm suggesting that one of his character, someone who is one of us but not one of us, is someone seeking an answer... mindless of the consequences... that's what I suggest."

"And Harry," she murmured, "you appear to have an idea of what you desire to do next."

"We look for anomalies," I explained firmly. "The Cronus Club looks for events which should not be happening in their time periods, changes to the normal course of things. I think I've found one."

"Where?"

"Russia."

She sucked in her teeth thoughtfully. "Have you spoken to the Club? To Moscow, St PetersburgaLeningrad, I suppose we must call it, ghastly though it is?"

"I sent them a message via Helsinki. I'm going to Finland tomorrow morning."