I worked until the day the farmer's wife sat down beside me and said, "I think you need to let it go."

She was a large woman, a black wig on her head, a black apron around her belly.

"This thing you carry inside you," she said at last. "I don't know what it is. I don't know where you got it. But Harry," and her hand slipped round the inside of my thigh as she spoke, "the past is the past. You are alive today. That is all that matters. You must remember, because it is who you are, but as it is who you are, you must never, ever regret. To regret your past is to regret your soul."

Her hand wandered up my leg. I caught it by the wrist before it could finish its journey and laid it carefully down in her lap. She sighed, turning her head slightly away, her shoulders to the side. "It was only a second," she explained. "For a second my hand touched yours, but that second is gone, and cannot be seen, heard or felt ever again. This second is gone too, the moment in which I spoke by your side. It is dead. Let it die."

So saying, she stood up briskly, patted down her apron, the skirt around her buttocks and back, and went back to work.

I left in the night, leaving not a sign behind.

Chapter 42.

Fifteen years earlier, and a few centuries later, and Pietrok-112 reminded me of that farm in Israel. Silence in the night, long, low sheds of bunks for its workers, a fence to cut it off from the rest of the worldaa hostile, frightening world of darkness and things that rattled in the night. Where the Golan Heights had stood above us as a monument to the god of another tribe, in Pietrok-112 the mountains were of unmarked concrete, temples to a new, rational deity of atoms and numbers.

I walked at the self-important speed of all managers visiting an insubordinate. There were more guards on duty by the first gate into that concrete canyon, which extended as far down into the earth as it did up. They looked at me with suspicion, but the deference of my escort gave me a certain credibility, and they asked no more.

Corridors of concrete beneath white strip lights; signs gave no more indication of which way to go than B1 or G2. Notices on the wall advised that radiation badges must be worn at all times, but it was no nuclear testing site. A poster showing the triad of scientist, soldier and happy industrial worker leading the way across golden fields, the sun glowing at their backs, reminded all passers-by of the bigger picture. Civilians were plentiful, mixed in among the guards. Lab coats were out, heavy quilted jackets were in, but the place was no industrial warehouse. Heavy shutters isolated the more sensitive areas, or access to them, with giant warnings proclaiming, NO UNAUTHORISED ACCESS.

The commander's office was a small raised room overlooking a delivery platform that led to the outside world. A black and white picture on the desk showed a man holding a very large machine gun, strings of bullets slung across his shoulders like a gangster's fashion prize. The radio was playing greatest communist hits of the 1940s, songs with refrains such as "We march through our brother's blood, raise our children to the sun" or "In the motherland we work for our loved ones and our comrades" and other poetic statements of intent. The commander himself was a man who'd been compressed to thinnessaa protruding nose and squashed face sat on a matchstick frame that could only have been achieved through some horrific medical accident. His brown eyes flashed up from a bank of telephones as we entered, and at the sight of me he barked, "What is this?"

Having begun boldly, I decided to continue so, and reaching into my pocket for my papers, making a show of having a hard time finding them, I barked, "Mikhail Kamin, comrade, state security. My office rang."

"Never heard of you."

"Then you should get a better secretary," I barked, "because I've been travelling for eight fucking hours to get here and I'm damned if I'm going to waste another second on some bloody memo. Have you received the latest description?"

The commander's eyes flashed from me to the private. This was a man paid to think, a man who really should not have permitted anyone to talk to him with less than suitable rifle-point deference. I could see his mind heading in a direction I didn't want it to go, so slammed my fist hard on to the tabletop to drag it back and snapped, "For Christ's sake, man, do you think the mole is going to sit around waiting for you to sort the paperwork out? We need to move now before he receives the warning."

Tyranny can do marvellous things for a person's independent will. The commander's eyes flashed to sudden, focused attention. "A mole? I've heard nothing of this. Who are you again?"

I rolled my eyes with a little too much drama, turned to the private and barked, "Youaout!"

He obeyed with the shuffle of a man not quite sure where his loyalty lies, mind going one way, legs taking him the other. I waited for the door to close, leaned forward on the table, looked the commander deep in the eye and said, "Get on the phone, and get me Karpenko."

Hesitation resolved itself into action.

"I don't know you," he repeated firmly. "You come in here, making these accusations..."

I pulled the gun from my pocket. The Mikhail Kamin papers came too, unprofessionally tangled up in the depths of my coat, but as they tumbled on to the table they only mildly undermined the emphasis of the moment. "Vitali Karpenko," I repeated softly. "Get on the phone and bring him here."

Heroism fought with pragmatism.

To my relief, pragmatism won. I really had no idea what I was going to do if it hadn't.

Chapter 43.

I will never fully understand the notion of a suicide mission. For us it is relatively simple, entailing only the considerable boredom of youth as its primary consequence. Certainly I regretted how likely it seemed that I was going to have to blow a hole in my own skull to escape the situation I had so effectively talked myself into, but by far the more intimidating prospect would have been capture and questioning, and I considered a few years' boredom to be infinitely preferable to that.

But I have seen men for whom death truly is the end walk towards their demise for reasons no greater than that it was what they were told to do. On the beaches of Normandy, where the bodies floated in the water beside the falling ramps of the landing craft, I saw men run into machine-gun fire who would say, "Hell, I never thought it would come to this, but now I'm here, what's a guy to do?" With no going back, and no going forward, they went to their deaths with no better plan immediately to hand, having gambled that their choices would not narrow so far, and having been found to be wrong.

For my part, it seemed likely that I would die in this place for little more than a speculation. For a crystal in a radio which was a few years ahead of its time; for the name of a man who saw the future; for a secret hidden by men with guns.

The commander was so good as to point all of this out to me. "You're going to die here," he explained as we sat in his office, waiting for Karpenko to come. "Make it easier for yourself."

I grinned. "Make it easier for yourself" implied that death was my primary concern, as well as being a phrase I associated with New York policemen rather than Soviet commanders in a hidden base. My levity surprised him, his thin grey eyebrows twitching over his paper face. "You're handling this very calmly," I pointed out, "for a man on the wrong end of a gun."

He shrugged. "I've had my time and lived it well. You, thoughayou are a young man. You will have things which tie you to this world. Are you married?"

"That's a very pious question," I answered. "Will it have the same emotional implication if I say that I enjoy living in sin?"

"What else do you enjoy? Perhaps you can enjoy them again."

"That's a really nice thoughta" I sighed "aand I'm grateful for it, but there comes a point when one realises that gratification of the flesh is only so fulfilling. It's fantastic while it lasts, but comes with so many questions of emotional baggage and doubt that frankly I begin to question whether the grief involved outweighs the satisfaction gained."

To my surprise, he raised his eyebrows. "You clearly aren't having the right sort of gratification."

"A professional ear masseuse in Bangkok once said exactly those words to me."

"You're not Russian," he suggested.

"Is there something wrong with my accent?"

"No Russian would do this."

"That's a terrible indictment of the Soviet spirit."

"You misunderstand. You do not appear to be in a fragile enough state to have chosen this as your particular suicide, and yet neither do you seem to have an agenda which could further the cause of others. I see in you no clear explanation for what you do..."

"So why assume I'm foreign?"

He shrugged. "Call it instinct." That was a little distressing. Instinct was one of the few factors which I had no great ability to alter or control. "Comrade," he went on, "you seem too intelligent to be doing this for nothing. Is there really no other path open to you?"

"None which engages me so much," I replied. A knock at the door cut short any further soul-searching. I gestured at the commander to be silent behind his desk and, tucking the gun into my coat, slipped on to the one stool besides his desk.

A nod, and the commander called, "Enter!"

The door opened. The man who came in was already in the middle of a sentence, which had clearly begun for him some several seconds before actually receiving permission to come inside.

"... very busy right now and really can't be-"

The sentence stopped.

The man looked from the commander to me, and his face broke into a smile. "Good God," he said, each word dropping like a pebble in a pond. "Fancy seeing you here."

Chapter 44.

Many lives ago, in that busy summer when Vincent Rankis and I first began to truly examine each other's minds, and before that cold night when he learned of the Cronus Club and left me with some light bruises and some heavy doubts for my pains, we went punting down the river Cam.

I have never liked punting, always feeling that, as means of transport went, it was one of the least sensible available and, more to the point, as it appeared to be practised in Cambridge, a skill as much valued in the incompetence as the mastery. A good trip on the river would not be complete for both students and some of my peers unless it involved hitting a bridge, causing a pile-up, running aground on a muddy bank, dropping the pole in fast-flowing waters and, ideally, at least one person falling in. I have similar feelings about gondolas in Venice, where the skill of the pilot is almost entirely cancelled out by the size of the fee and the sense that you are, in your own naive way, contributing to a cliche that will in later years serve more gondoliers to defraud more tourists of their cash.

"That's your problem, Harry," Vincent had explained. "You've never understood the concept of doing things by halves."

I had grumbled my way to the riverbank, and grumbled my way on to the punt, and grumbled as we bumped our way between students, and grumbled as Vincent opened up his wicker basket, packed for the purpose, to produce flasks of gin with a dash of tonic, and perfectly cut cucumber sandwiches.

"The cucumber sandwiches," he'd explained, "are vital if we are to fulfil our roles."

"What are our roles?" I sulked.

"We are the living proof of the notion that rationality and intellectual vigour are slaves to social pressure and pleasant sunlight. For you and I may know, Harry," he exclaimed, sloshing the pole through the water with pointed enthusiasm, "that this is a truly ridiculous pastime for any self-respecting scholar of the universe to indulge in, and yet, for no rational reason that I can possibly devise, this is what must be done."

Our companions giggled.

I wasn't at all convinced by Vincent's choice of associates for this trip. I'd only met them at the riverbank, and their presence had further added to my sense of impending doom. She was Leticia, and she was Frances, but which was which I still couldn't quite put my finger on. They were dressed very properly in high-buttoned summer dresses and with their hair immaculately curled by their ears, but alas, from their propriety also came their frivolity, for they knewaof course they knew!athat taking a punt ride with two young bachelors in the summer sun was very much something Mother Would Not Approve Of, and any other thoughts they might have had on the course of our journey were rather subsumed by this all-encompassing revelation.

"Leticia's father is something in biochemistry," Vincent whispered in my ear, "and Frances has been claimed, apparently, by Hugh, who's a thoroughly repugnant creature but is playing tennis today down on the lawns. When we get there, Harry, I'm afraid it's either your or my ghastly duty to ensure that one of us kisses Frances on the lips, for Hugh to see; better not get the timing wrong, else we'll have to go through the entire procedure again until he notices."

I begged tutor's privilege, announcing it was bad enough to be seen to be on the river with students, let alone kissing one. Vincent sighed profoundly, and when we got to the lawns he did, indeed, as promised, contrive to drop the pole into the river and insist that myself and Leticia paddle against the current to collect it while he engaged in the loud and important business of temporarily seducing Frances. The calamity of our situation drew everyone's attention; the sight of the small, slightly round figure of Vincent entering into a sensual embrace with the spry Frances held it, and his work was done.

To my surprise, as I dried my freezing hands on my trousers and returned the pole to the safety of the punt, I realised I was laughing. Quite when the absurdity of the situation had begun to outweigh my resentment at its circumstances, I couldn't say, but no matter how hard I tried, I found it almost impossible to maintain a foul mood. Even the cucumber sandwiches, thin, tasteless and forlorn, entertained me for all of the above qualities. I had a worry that Leticia, feeling left out, expected me to do something sensual with her too, and my polite refusals to do so led to a rumour within the campus that I was, in fact, gay and enjoyed Vincent for his body, not his mind.

"Damn me, it's nice that someone does," said Vincent when the rumour reached his ears. "It's a lot of hard work, falling back on intellectual brilliance and emotional intelligence to seduce girls these days."

Should I have seen the clues?

Should I have spotted what Vincent was?

He was a novelty. He was unusual, ridiculous, brilliant, sombre and absurd. He was innovation in a stodgy town. When the day was done, and our companions had been returned to the stony embraces of their families, unsullied if not uncorrupted, we sat in my rooms, drinking the last of the ginaa nearly empty bottle being far sadder, in Vincent's mind, than a finished oneaand discussed once again the perpetual subject of Vincent's final-year thesis.

"I don't know, Harry. None of it seems really... important enough."

Not important enough? The turning of the stars in the heavens, the breaking of the atoms of existence, the bending of light in our sky, the rolling of electromagnetic waves through our very bodies...

"Yes yes yes." He flapped his hands. "That's all important! But ten thousand words of thesis is... well, it's nothing, is it? And then there's this assumption that I should focus on one thing alone, as if it's possible to comprehend the structure of the sun without truly understanding the nature of atomic behaviour!"

Here it was again, the familiar rant.

"We talk about a theory of everything," he spat, "as if it were a thing which will just be discovered overnight. As if a second Einstein will one day sit up in his bed and exclaim, 'Mein Gott! Ich habe es gesehen!' and that's it, the universe comprehended. I find it offensive, genuinely offensive, to think that the solution is going to be found in numbers, or in atoms, or in great galactic forcesaas if our petty academia could truly comprehend on a single side of A4 the structure of the universe. X = Y, we seem to say; one day there will be a theory of everything and then we can stop. We'll have wonaall things will be known. Codswallop."

"Codswallop?"

"Codswallop and barney," he agreed firmly, "to paraphrase Dr Johnson."

Perhaps, I suggested, the fate of the universe could briefly take second place to the thorny issue of graduating with honours?

He blew loudly between his lips, a liquid sound of contempt. "That," he exclaimed, "is precisely what's wrong with academics."

Chapter 45.

"Good God," he said. "Fancy seeing you here."

He was only a few years older since I'd seen him last, those centuries ago, still a fresh-faced young man barely clipping his early thirties. Somehow he'd managed to find a pair of grey suit trousers and well-kept brown leather shoes, polished up bright to wear. An oversized greenish tunic was more in keeping with his Soviet style, and a thin beard of fragile curls was an attempt to enhance his age, and he was Karpenko, and he was Vincent Rankis. He was followed almost immediately by two armed guards, rifles raised. They at once shouted at me to get down, to put my hands above my head, but he silenced them with a gesture.

"It's all right," said the man known as Karpenko. "Let me handle this."

Vincent Rankis, sometime student, as British as they came, his Russian flawless, his eyes full of recollection. The night he'd attacked me in Cambridge, he'd also vanished from his rooms. I'd used every resource in my power to track him down, but every name had led to an empty nothing, every enquiry ended in a failure. Vincent Rankis, I'd been forced to conclude, had, legally speaking, never existed. But then neither had I.

For a moment I couldn't speak, all the tactics and questions I'd had in mind briefly suspended at the sight of him. He took the opportunity to flash me a brilliant smile, before glancing at the commander and saying, "Comrade, may I have the room?"

The commander looked to me, and through lips turned to sand I mumbled, "Fine by me."

The commander rose carefully, walked to Vincent and paused, turning his head by the young man's side to murmur, quietly but audibly, "He has a gun."

"That's fine," replied Vincent. "I'll handle it."

With a nod, he dismissed the other soldiers and, moving around the commander's desk, settled himself down in the large chair with an easy confidence, folding his fingers together in front of his chin, elbow resting on his crossed-over knee.