Petrie turned to Shtyrkov. 'I see what you mean, Vashislav. Youre all paranoid lunatics.

Freya said, 'Tom, wed better get started.

'Can I work alone? I concentrate better that way. I can talk to myself, walk up and down and so on.

Gibson said, 'You can have the theological library. In fact, you can have the entire Hapsburg Empire if it will get us the answer. Take one of the Alphas. What about you, Freya? Are you a social misfit too?

Freya was already tapping at a keyboard. 'Im a party-goer, Charlie. Here is fine.

The Alpha was heavy but Shtyrkov shared the weight, while Gibson trailed behind with a terminal. After some fussing Petrie found plugs near a walnut desk. He cleared the computer printouts from the floor and the central table. Gibson disappeared and returned with a ream of A4 paper and a small disk. 'Watch out for the cleaners, he said. 'Security!

At last Petrie was alone. He took the time to absorb his amazing new office.

It was baroque, windowless, lined with gilded, carved bookshelves reaching to the ceiling and brightly lit with overhead spotlights. There was an upper gallery accessed by a spiral staircase in a corner of the room. The books were old, although many had been rebound. They must have taken centuries to collect and had no doubt been confiscated from some monastery by some thieving emperor, maybe the guy now looking down his nose at Petrie from his white horse. He browsed at random through some of the books. Most of them were in Latin, but a few were in some unfamiliar script which he a.s.sumed to be Czech or Slovakian. They seemed to span many centuries and many topics: there were ill.u.s.trated herbals, travelogues, human anatomies, atlases, military manuals, alchemists prescriptions, star charts and lists of wonders: two-headed cattle, serpents swallowing ships at sea, mysterious lights in the sky.

Then he sat down on a blue-upholstered chair, switched on, fed the contents of the CD into the computers memory, and settled down to examine the cosmic blizzard which had briefly swept through the underground lake.

At first, Petrie made no attempt to a.n.a.lyse what he was seeing. Svetlana had a little three-dimensional picture of the lake, in blue, complete with underground scaffolding and little red spots to mark the positions of the light detectors. A white line appeared briefly through the far edge of the lake, at an angle, while t = 00m 00.000s appeared at the top right-hand corner of the screen. Following Svetlanas instructions in the readme file, he tapped the return b.u.t.ton a few times, speeding the movie up. A second white line appeared at t = 03m 40.414s precisely, parallel to the first but nearer the lakes centre. At t = 07m 20.829s a third line appeared, right of centre, making a neat right-angled triangle with the first two. It was followed a few seconds later by nine more, left to right across the lake. One-two-three near, one-two-three middle, one-two-three far; a neat rectangular grid.

It was as if the particles were being used to probe the lake, find its outline in the cavern.

Petrie dismissed the idea instantly; it was, quite simply, impossible. The apparent probing had to be luck.

He pushed the animation on a bit and was immediately faced by a white-out, the blizzard of parallel lines obscuring Svetlanas picture of the lake and its scaffolding.

He slowed it down to the point where he could just make out the ebb and flow of individual streaks. He was now looking at snowflakes in a blizzard. He let it run, still making no attempt to make sense of it. After an hour he pressed a b.u.t.ton and the animation froze. Time elapsed read t = 07 m 22.440 s; in real time, the flow he had been looking at for the last hour had pa.s.sed through the lake in just over a second and a half.

He went back to the beginning and started again. And again he saw the right-angled triangle, the rectangular grid, the sudden blizzard. Now Petrie ran the blizzard for three solid hours, staring at the hypnotic flickering lines, while a dull ache at the back of his neck spread up over his head and down to his eyes, which began to close up.

Yes, there was a pattern. But it was the pattern of any blizzard. Pauses, swirls, brief bursts, spa.r.s.e areas and concentrations. Who was to say what realms the particles had pa.s.sed through on their interstellar journey, and what forces had buffeted them on the way? There was no more reason to suppose the patterns were meaningful than there was to suppose that the wind was intelligently directed. What was that Elton John song? Something about a candle in the wind.

And yet ...

Something about the patterns. Groups of four. Something trying to surface. An eightsome reel dancing in his head. No, a foursome reel. No, a room full of whirling reels, patterns dancing like Tam OShanters witches. But, frustratingly, nothing that he could put into words or even formulate abstractly.

A knock on the door. Svetlana. 'Join us for lunch? She saw the strain on the mathematicians drawn face and added, 'Have you found something?

Petrie shook his head. Suddenly aware that his bladder needed relieving, he waved Svetlana ahead. He followed her along the corridor. She was trailing a whiff of perfume. Or maybe it was shampoo Petrie wasnt into the things women sprayed themselves with. She pa.s.sed behind the curved stairs. Gibson, climbing them with a burger in one hand and a mug in the other, called down. 'Found anything, Tom?

'Give me a chance, Ive just arrived.

In the kitchen, Shtyrkov was loading a dumb waiter with half a loaf of bread, b.u.t.ter, jam, biscuits and a plate piled with beetroot and what looked like a squashed octopus. Svetlana rattled a pot on to a big electric hob. 'Im making myself some pasta, Tom.

'No, thanks. Ill just get back to it. Petrie poured himself a coffee from a bubbling percolator, helped himself to a couple of chocolate biscuits from Shtyrkovs dumb waiter collection and disappeared back to his baroque study.

This time he ran the animation for six hours. Apart from one visit to the bathroom, and one to the kitchen for water to relieve his parched throat, he never stirred from his chair. Gradually, as the swirling patterns saturated his brain, an unwelcome image kept forcing itself forward. He tried to reject it, concentrate on the patterns, but it kept coming back. It was a memory of Sampson-Kildare, his sixth-form English teacher, a vile old lecher. The man was thrusting his wrinkled, leering face into Petries, and he was croaking: 'The mirth and fun grew fast and furious, while the patterns danced like Tam OShanters witches, and another image, incredible and malign, slowly crawled out from his unconscious mind.

8.

Decode 'Look at you! Youve got to eat.

Petrie stared dully at Freya. It was some seconds before he brought himself back from his world of swirling blizzards. 'Whats the time?

She looked at the clock on his terminal. 'Just after eleven. The others have eaten.

'Im not hungry.

'You are. And Vashislavs made something for us.

'Its probably squashed octopus.

'What?

'Never mind. Okay, Ill be along.

She took him firmly by the arm. 'Nice try, but youre coming now.

'You remind me of my mother.

Shtyrkov had been busy. Freya steered him to the first-floor canteen, if canteen was the word for the chandeliered elegance and gleaming silverware which greeted him. She sat him down at a table set for three, spread with a white tablecloth. He surveyed the bowls with brown bread, olives, gherkins, salad and fruit. A bottle of vodka took pride of place at the centre of the table. Through the windows, a flicker of distant lightning briefly lit up heavy clouds and forested hills.

'Where are Charlie and Svetlana?

Freya poured the vodkas. 'Gone to bed. She smiled mischievously. 'Separate beds, that is. Are you making progress?

Petrie ma.s.saged his forehead. He felt as if his head was splitting in two. 'Maybe. I dont know. Where does the food come from?

'Theres a big freezer. And Vash tells me fresh food will come with the cleaners in the mornings. Theyll be here for an hour each day. The castle administrator is keeping out of it but Charlie has his home number if we need anything.

'An entire castle to ourselves. He carries some clout, does our Russian colleague.

'And I can cook, Shtyrkov boomed, appearing from a side room with a tray. 'A talent which I owe to my Great-aunt Lidia. First, we have caviar. He set a large bowl of some chilled puree on the table and sat down heavily. 'Poor mans caviar, that is. A Georgian spread made of aubergines, tomatoes, garlic, sugar, lemon juice and pepper. Tom, tell us what you have found.

'Nothing.

Shtyrkov smiled sceptically. 'You are a bad liar. You can hardly keep your eyes open. Something is driving you.

d.a.m.n the man. Im not ready to talk about it. 'Maybe something.

Freyas eyes widened. 'Maybe something? What exactly?

Petrie spread the fake caviar on a hard, flat square of bread. It was his first taste of food since Shtyrkovs commandeered biscuits and he savoured the sharp, tangy taste. He wiped his mouth and said, 'Patterns. But no more than gusts of wind in a storm. Who knows what furnace these things came out of? I dont see evidence of an intelligence lying behind them.

Shtyrkov seemed unperturbed by Petries negative comment. He smiled slyly and poured vodka to the brims of their vodka gla.s.ses. He nodded at Petries T-shirt. 'You play chess?

'Sort of. Come on, Vash, what makes you think theres something in that particle burst?

Shtyrkov raised four fat fingers. 'Yon. Tesera. Chetire. Cuatro. Quattre. Quattro. Vier. Four.

Petrie looked at the Russian with astonishment. Groupings of four, additions up to four, foursome reels, the bewildering fact had come to Petrie as the merest glimmer after hours of mind-breaking work. He said, casually, 'Okay. But I cant make sense of it. Not yet.

Shtyrkov grinned but said nothing. Freya poured tea.

'People have always a.s.sumed that extraterrestrials, if they exist, would send out radio signals, Petrie said. 'n.o.body thought about weird particles.

Shtyrkov sipped the vodka with satisfaction. 'Ice cold, as it should be. Extraterrestrials, however, may not feel bound by our limitations.

'A Harvard/Princeton team are searching for laser pulses, Freya said. 'Theyre using a modest telescope and they could pick up signals out to a hundred light years, maybe a thousand.

'And let me tell you why, young Miss Freya, or has Anglo-Saxon angst spread to Norway and you prefer Ms?

Freya laughed but didnt rise to Shtyrkovs provocative bait. The Russian continued, 'Bandwidth. Red light has a frequency thirty thousand times higher than microwave radio. In the time taken for a radio wave to arrive, thirty thousand light waves do so. Information is transmitted thirty thousand times faster. Equipment is smaller and more mobile: an intelligence could easily fire signals at ten solar systems a second if it was trying to make contact with other life forms. And one other thing. The Galaxy is awash with radio waves, from pulsars, nebulae, even stars. But I very much doubt if, anywhere, Mother Nature fires nanosecond laser pulses. Find one and there can be no confusion with a natural source.

There was a rumble and lights flickered briefly. Petrie felt the icy vodka burning his lips and then warming his alimentary ca.n.a.l all the way down to the stomach. 'You mean, why use radio when you have lasers?

'Why have cotton when you can have silk? Radio searches happen now because they happened first. They are an accident of history, a hundred-year slice of our technological evolution. Better means to communicate already exist.

'If youre operating on timescales of thousands or millions of years, lasers may have a short shelf life too.

Shtyrkov nodded. 'Exactly. To an advanced signaller, they would have the byte rate of smoke signals. You learn fast, young Tom. And because the higher the frequency the more efficient the communication, why stop at electromagnetic radiation at all? Weird particles, as you call them, carrying energy beyond even gamma rays, would be much more effective at transmitting information. A few thousand years down the line and we too will be firing them into s.p.a.ce.

'I ought to get back to it. Petrie pushed back his chair.

Shtyrkov was heaping Georgian caviar thickly on to flat bread. 'Tom, bypa.s.s a thirty-year learning curve by absorbing the following truth, from Ecclesiasticus chapter 38, I think: "A scholars wisdom comes of ample leisure." Did Plato rush to catch a bus? Was Socrates ever twitching to get back to his computer terminal? My chicken tabaka is flattened, fried, crisp and juicy, and it is ready. Ready, that is, to serve with a prune sauce, sour cream and red pickled cabbage. Now, do you propose to insult me by refusing my laboriously prepared feast?

'If you put it that way.

There was a bright flash, and this time the rumble of thunder was closer.

Freya spoke firmly. 'Look at you, Tom. You can hardly keep your eyes open. When weve eaten, Im taking you to bed.

Petrie thought that Freyas command of English was probably less than perfect.

Petrie needed sleep. He had to lie down, put his head on a pillow, shut his eyes and sleep.

Freya, it seemed, had adopted the role of a surrogate mother. After Shtyrkovs main course a squashed chicken rather than a squashed octopus exhaustion had overcome Petrie to the point where he could hardly stand up. Freya had taken him by the arm and led him up the stairs. Even in his exhausted state he had enjoyed the warmth, the scent, the animal femininity of this young Norwegian woman. She had gently eased him into his room and wished him a good night.

He threw off his clothes, pulled down the blankets and flopped.

But the blizzard was still swirling. Petrie could see it in the ceiling, and on the walls, and in all the dark corners of his room.

This was different from Bletchley.

In war, strenuous efforts were made to veil the message. Victory and defeat in battle, and even the outcome of a war, might nowadays depend as much on a contest between distant mathematicians as it once did between armies. If the Germans had known about Bletchley, they might have changed the course of the war with a single bombing raid. But if Shtyrkovs lunatic conjecture was right, n.o.body would be trying to hide anything. On the contrary, the signallers would be trying to communicate.

Even so, Petrie thought, his mind whirling, exhausted but unable to stop, how can they judge the mental level of the people theyre trying to reach? He could still be an ape trying to understand a Fortran computer program.

He heard Freyas door closing next to him, visualised her taking her clothes off, sliding naked between sheets, just a few feet away.

As he drifted off, rain began to batter against the window. And once again Sampson-Kildare, the old horror, was croaking: 'The wind blew as twad blawn its last; The rattling showers rose on the blast; The speedy gleams the darkness swallowd; Loud, deep and lang the thunder bellowd: That night, a child might understand, The Deil had business on his hand.

And now Sampson-Kildare was high on a ledge in the big cavern, shooting bullets through the lake. He paused to reload his machine gun, but only for a microsecond. The next burst of fire was somehow different from the one before. And then another tiny time gap, and another surge of bullets.

And the bullets were going through the lake faster than light and the lake was glowing and Sampson-Kildare was saying thats because the eye cant see flickering faster than a fiftieth of a second in duration, and he was sometimes firing millions of bullets through the lake in a microsecond, and at other times he was smoking and firing only a few thousands at a time.

And the bullet patterns were sometimes filling just one patch of the lake, or sweeping round it like a searchlight.

And yet not like a searchlight. It was more of a corkscrew or spiralling motion.

No, more like two searchlights, counter-rotating. And now there were two machine-gunners, the surface of the lake spitting as the stream of bullets danced around each other like a gunfighters ballet, and Sampson-Kildare was leaping around grotesquely on the ledge and croaking: 'As Tammie glowerd, amazd, and curious, The mirth and fun grew fast and furious; The piper loud and louder blew, The dancers quick and quicker flew, They reeld, they set, they crossd, they cleekit...

BANG!.

Rattling windows; a flash of light penetrating his eyelids. Petrie wakened with a gasp, staring into the dark. Heavy rain was battering on his window.

Impossible! Utterly impossible!

He threw back the blankets, groped for a light and dressed quickly. Shaking, he went out into the darkened corridor and felt his way along it. He could just make out the top of the marble stairs. Another flash momentarily lit them up and he descended cautiously, his eyes adapting to the dark. The headache had gone.

He hurried along to the theological library and groped for light switches. There were three of them and he switched them all on. He realised that he had left his computer running. To his relief, as he tapped at the keyboard, he found that the thunderstorm hadnt affected it.

He looked again at the particle storm on his screen. Parallel lines, and yet, not just parallel lines. The particles didnt like to crowd too close together. Petrie thought this might be down to their physics: maybe they repelled each other at short range or whatever. Nothing to do with aliens or similar rubbish.

There had always been a slightly mad streak running through Russian science. The Tunguska meteorite was a crashed flying saucer, or the innermost satellite of Mars was an ancient s.p.a.ce station, c.r.a.p like that. Maybe Shtyrkov was part of that tradition.

And in any case, order could be created out of chaos. Petrie thought there were maybe complicated force laws between the particles and that these forces had generated patterns during the long interstellar journey.

He rubbed his face with his hands and groaned with tiredness. Belousov and Zhabotinskii, more d.a.m.ned Russians. Theyd mixed citric and sulphuric acids, added salts and chemicals, and within the mixture, as by a miracle, wonderful red-blue pulsations had appeared, and circular waves had come and gone, and spiral patterns had chased each other around the mixture. And it had all grown just from chaos, from the disequilibrium of the chemical mixture. Theyd been beaten to their discovery by forty years, by William Bray, but his contemporaries hadnt believed you could get chemical reactions to oscillate, hadnt bothered to follow it up, and the man had died in obscurity, the Russians now collecting the kudos denied Bray by the idiocy of his colleagues.

Instead of looking at an indecipherable ma.s.s of lines, why not reduce each particle to a point? Imagine a flat surface, face-on to the flow, and record each particles point of intersection with the plate. Like a telescope pointing to the signal source.

That would take programming. h.e.l.l, the Earths rotation.

Svetlana!

He ran back through the corridors and up the stairs. One, two ... seven doors along. He knocked sharply. The sound of a body stirring within. 'Svetlana!