I stepped toward the big gear-laden table. I could smell Johnson's Pledge, I realized, and it struck me that the Thunderbird toy had been free of dust. Up on the desktop screen was what looked like a prototype Web page. It was complex, crowded, and partly animated; it showed stanzas of music that cycled rapidly, along with a kind of binary code I didn't recognize. Peter stood awkwardly beside the table, big hands wrapped around his coffee cup.

"This is your work?-Peter, I hate to admit it, but I don't know a d.a.m.n thing about what you do now you're retired from the cops."

He shrugged. "After the funeral you had other things on your mind." There was a note in his voice, a subtext.I'm used to it. "But you got interested when you saw me on TV. Well, that's okay. I make a living from Web design, mostly corporate sites, and game design."

"Games?"

"Web-based, multiuser. I was always good at computer games. It's something to do with a facility for spotting patterns in patchy and disparate information, I think. It made me a good copper, too. That and being out of control."

"Out of control?"

He grinned, self-deprecating. "You knew me, George. I was never much in control of anything about my life. I was always awkward socially-I could never figure out what was going on, stuff other people seemed able to read without thinking about it." He was right about that. In later years, we, his friends, even speculated he might be mildly autistic. He said, "You see, I'm used to being in situations where I don't know the rules, and yet making my way forward anyhow. Decoding a chaotic landscape."

"So is this one of your games?"

"It's a personal project."

I pointed at the screen. "I see music, but I don't recognize it. Some kind of encryption system?"

"Sort of, but that's not the purpose." He seemed briefly embarra.s.sed, but he faced me, determined. "It's a SETI site."

"SETI?"

"Search for Extraterrestrial Intelligence."

"Oh, right."

He talked quickly. "We've spent forty years now listening for radio whispers from the sky. But that's twentieth-century thinking. If you were an ETI, and you wanted to learn something about the Earth, what would you study? What better than the Internet? It's by far the largest, most organized information source on the planet."

I said carefully, "You imagine aliens are logging on?"

"Well, why not? You'd learn a lot more about humankind than by sticking a probe up the r.e.c.t.u.m of a farmer from Kansas." He seemed to sense what I was thinking. He grimaced. "Let's just say I've been intrigued by the possibility of extraterrestrial life on Earth since the first showing ofFireball XL-Five .

Haven't you?"

"I suppose so. But you've stayed interested. You've become-um, an expert on this stuff."

"As much as anybody is. I'm plugged into the right networks, I suppose. My name is known. Which is how I got on the TV."

"And your site is designed to catch their attention?" I peered at it. "It looks a little busy."

"Well, I doubt an ETI is going to be interested in snazzy Web page design. The site is information-rich, though-you're looking at the works of Chopin, here, rendered in compressed binary-and encoded in forms that ought to make it easy for the ETIs to pick up. Bait, you see. And if the ETIs do find my site- look, this is a long shot, but it's cheap to set up and maintain . . . and the payoff would be of incalculable value. Isn't it worth trying? I'm not alone in this," he said, a bit defensively. "There's a network of researchers, mostly in the States . . ."

He told me something of a bizarre-sounding online community of like minds. "We call ourselves the Slan(t)." He had to write that down for me. "Slanis an old science fiction reference-made up to date, you see . . . It sums up how we see ourselves. The Slan(t)ers are a new kind of community, a bunch of outsiders, the fringe united by new technology."

"I bet there are a lot of Californians."

He grinned. "As it happens, yeah. It was set up long before I joined." He said there was no hierarchy to Slan(t); it was all "bottom-up." "It's a self-organizing community. The hardest thing to model online is social interaction-the kind of unconscious feedback we humans give each other face to face, feedback that moderates behavior. So we devised a system where we would moderate each other's contributions to the clickstream. If you are uncivil, or just plain uninteresting, your scores go down, and everybody sees."

"A bit like eBay."

"Like that, yes."

"Plenty of scope for bullying."

"But that's antisocial, too, and there are always plenty of people who would mark the bully down accordingly. It works. It is homeostatic-actually another example of feedback. But this time it'snegative feedback that tends to make a system stable, rather than drive it out of control." He talked on, describing the Slan(t)ers' projects.

I felt awkward. This was the kind of conversation we'd had as kids at school, or later as booze-fueled students: excitable, complex, full of ideas, the more outlandish the better. Peter had always been good at that, because he'd learned to be. Whereas other fat kids, it's said, get a break from bullying by being funny, Peter's defense was to have wilder ideas than anybody else. But now it wasn't the same. We weren't kids anymore.

And there was something else I couldn't quite read in the way he spoke, this big, clumsy man with folded hands and his habit of adjusting invisible spectacles, talking earnestly. I had the impression of shadows, ranked behind him in the electronic dark, as if Peter was just a front for a whole network of densely interconnected, like-minded obsessives, all working for ends I didn't understand.

Anyhow Slan(t) sounded like one giant computer game to me. "Interesting."

"You don't really think so," he said. "But that's okay."

"But now," I said, "perhaps we do see the aliens, in the Kuiper Anomaly. Isn't that what you've been saying on TV?"

"That's obviously a gross signature of something out there. Yes, it's exciting." His face was closed. "But I have a feeling that the origin of the Anomaly is going to turn out to be stranger than we think. And besides, it's not the only bit of evidence we have."

"It isn't?"

"Perhaps thereare traces out there, if you know how to look. Traces of life, of other minds at work. But they're fragmentary, difficult for us to recognize and interpret. But I, well, as I told you I have this facility for pattern matching."

I looked into my coffee cup, wondering how I could get out of the conversation politely.

But he had rotated his chair until he faced the desktop, and was briskly working a mouse. Images flickered over the screen. He settled on a star field-obviously color-enhanced-the stars were yellow, crimson, blue, against a purple-black background. Around a central orange-white pinpoint were two concentric rings, like smoke rings. The inner one was quite fine, but the outer, perhaps four times its diameter, was fatter, brighter. Both the rings were off-center, and ragged, lumpy, broken.

I searched for something to say. "It looks like aFireball XL-Five end credit."

Sometimes he lacked humor. "Fireballwas in black and white."

"Tell me what I'm seeing, Peter."

"It's the center of the Galaxy," he said. "Twenty-five thousand light-years away. A reconstruction, of course, from infrared, X-ray, gamma ray, radio images, and the like; the light from the center doesn't reach us because of dust clouds. The sun is one of four hundred billion stars, stuck out in a small spiral arm-you know the Galaxy is a spiral. At the core, everything is much more crowded. And everything is big and bright. It's Texas in there." He pointed at the image. "Some of these 'stars' are actually cl.u.s.ters.

These rings are clouds of gas and dust; the outer one is maybe a hundred light-years across."

"And the bright object at the center-"

"Another star cl.u.s.ter. Very dense. It's thought there is a black hole in there, with the ma.s.s of a million suns."

"I don't see any aliens."

He traced out the rings. "These rings are expanding. Hundreds of miles a second. And the less structured clouds are hot, turbulent. It's thought that the big rings are debris from ma.s.sive explosions in the core.

There was a giant bang about a million years ago. The most recent eruption seems to have been twenty- seven thousand years ago. The light took twenty-five thousand years to get here-it arrived about two thousand years ago; the Romans might have seen something . . . If you look wider you can see the debris of more explosions, reaching much deeper back in time, some of them still more immense."

"Explosions?"

"n.o.body knows what causes them. Stars are simple objects, George, physically speaking. So are galaxies, even. Much simpler than bacteria, say. There really shouldn't be such mysteries. I think it's possible we're seeing intelligence there-or rather stupidity."

I laughed, but it was a laugh of wonder at the audacity of the idea. "The Galaxy center as a war zone?"

He didn't laugh. "Why not?"

I felt chilled, but I had no clear idea why. "And how does Kuiper fit into this?"

"Well, I've no idea. Not yet." He pulled up an image of his own face on CNN. "I'm hoping that if I can tap into the interest in Kuiper, I'll get resources to push some of these questions farther. For instance, there may be links between the core explosions and Earth's past."

"Links?"

"Possibly the explosions tie in with extinction events, for instance."

"I thought an asteroid impact killed off the dinosaurs."

"That was a one-off. There have been eighteen other events. You can see it in the fossil record. Eighteen that we know of . . ."

I lifted my mug to my lips, but found it drained of coffee. I put the mug on the computer table and stood.

"I ought to start my day."

He looked at me doubtfully. "I've gone on too long. I'm sorry; I don't get much chance to talk; most people wouldn't listen at all . . . You think I'm a crank."

"Not at all."

"Of course you do." He stood, looming over me, and grinned. Again there was that disarming self- deprecation, and I sensed, uncomfortable again, that he really was glad to have renewed his connection with me, regardless of my reaction. "Maybe I am a crank. But that doesn't mean the questions aren't valid. Anyhow, you're the one with the abducted sister."

"That's true. I ought to go."

"Come back and tell me what you find."

Chapter 7.

Magnus sat cross-legged, hunched over the little wooden game board.

Magnus was a great bear of a man with a head the size of a pumpkin, it seemed to Regina, a head so big his helmet seemed to perch on top of it. But then, his helmet wasn't actually his but had been pa.s.sed on to him from another soldier, just as had his sword and shield. Meanwhile his cowhide boots and his woolen tunic and hiscucullus , his heavy hooded cloak, had all been made in the village behind the Wall, nothing to do with military issue at all. That awkward secondhand helmet had a dent in it, big enough to have held a goose's egg. Regina wondered sometimes if the mighty blow that had inflicted the hollow had been the cause of the original owner's "retirement."

For all his bulk Magnus was a patient man, which was why Aetius approved of him as a companion for Regina. After five years on the Wall she thought she knew her way around, but some of the rougher soldiers, she had been told in no uncertain terms, werenot suitable companions for the prefect's twelve- year-old granddaughter.

Magnus was a good man, then. But he was soslow . His great ham of a hand hovered briefly over the board, but then he withdrew it.

"Oh, Magnus, comeon ," Regina pleaded. "What's sodifficult ? It's only a game of soldiers, and we've barely started. The position'ssimple ."

"We haven't all got a prefect's blood in our veins, miss," he murmured laconically. He settled himself more comfortably, his spear cradled against his chest, and resumed his patient inspection of the board.

"Well, my backside is getting cold," she said. She jumped to her feet and began to pace up and down along the little tiled ridge behind the battlements.

It was a bright autumn day, and the northern British sky was a deep, rich blue. This was a sentry's lookout point, here on the wall of the fortress of Brocolitia-in fact, strictly speaking Magnus was on sentry duty right now-and she could see across the countryside, to the farthest horizon in every direction. The land here was rolling moorland, bleak even at the height of midsummer, and as autumn drew in it was bleaker still. There was no sign of life save for a single thread of black smoke that rose toward the sky, far to the north, so far away its source was lost in the mist that lingered even now, so close to noon.

And if she looked to left or right, to east and west, she could see the line of the Wall itself, striding away across a natural ridge of hard, black rock.

The Wall was a curtain of tiled brick and concrete, everywhere at least five times a man's height. A steep-sloped ditch ran along the north side. It was clogged with rubbish and weeds-and in some places the detritus of battles, broken sword blades and dented shields and smashed wheels; sometimes the hairy folk from the north would creep down to scavenge bits of iron. To the south, beyond the line of the road that ran parallel to the Wall, was another broad trench called thevallum . Thevallum had been filled in here and there, to provide easier access between the fortresses on the Wall itself and the muddy little community of huts and roundhouses that had, over the generations, grown up to the south.

It was thrilling to think that the Wall's great line was drawn right across the neck of the country. On a clear day she could see the sentries walking back and forth along its length, all the way to the horizon, like ants on a bit of string. And while on the north side there was nothing but moorland, heather, and garbage, on the south side there was a whole string of communities, inhabited by the soldiers and their families, and those who lived off them. It was like a single town, some of the soldiers said, a Thin Town eighty miles long, a belt of drinking and whoring and c.o.c.kfighting and gambling, and other vices she understood even less.

But much had changed during the Wall's long lifetime-so she had learned from Aetius's dogged teaching. The threat the Wall faced had evolved. Compared to the scattered, disunited tribes faced by Hadrian who'd built the Wall in the first place, today's great barbarian nations, like the Picts to the north of the Wall, were a much more formidable proposition.

Once, Aetius said, the Empire's military might had been like the snail of a sh.e.l.l: break through it and you were into the soft, defenseless core of the settled provinces. After the disastrous barbarian incursions of the recent past, that lesson had been learned well. For all its imposing presence, today the Wall was only part of a deep defensive system. Far behind the line of the Wall there were forts in the Pennines and farther south, from where any barbarian incursion could be countered. And north of the Wall itself there were more forts-though few of them manned these days. More effective were thearcani who worked among the northern tribes, spies spreading dissension and rumor and bringing back information about possible threats.

Regina had grown to love the Wall. Of course it showed its age. Much of this old fortress had been demolished or abandoned, for much smaller units were stationed here now. And time had inevitably ravaged the great structure. Some of the repair work was visibly cruder than the fine work of earlier generations-in places the old stonework had even been patched up with turf and rubble. But the barbarians had always been pushed back, the Wall reoccupied, the damage by friend or foe repaired, and so it would always be. In the five years since Aetius had brought her here, enclosed by its ma.s.sive stones, she had come to feel safe, protected by the Wall and the power and continuity it represented.

Conversely, though, she was p.r.o.ne to anxiety over the future. Overall there were far fewer soldiers in Britain than in the past, Aetius said: perhaps ten thousand now, compared to fifty thousand before the disastrous imperial adventure of Constantius, which had stripped Britain of its field troops. Two nights ago a red glow had been easily visible in the night sky to the east, and in the morning there was a great pall of smoke, coming from the direction of the next fortress to the east, Cilurnum. Troops had been dispatched there to find out what had happened, and hadn't yet returned-or if they had, Aetius wasn't saying so to her. Well, there was nothing she could do about that.

Regina shivered, and rubbed her arms to warm up. The Wall might be a safe place, but it was uncomfortable. The great ma.s.ses of stone retained the cold all through the day. After five years here, though, she had gotten used to the brisk climate and needed nothing more to keep her warm but her thick woolen tunic. And she had learned never to complain about the rigors of life here, so stripped-down compared to life in the villa, which she still remembered brightly. She had no wish to be called a spoiled child again, even though she knew that as the granddaughter of the prefect she was given special privileges.

". . . Ah," Magnus said.

She walked back to him. "Don't tell me you've moved at last, O Great General."

"No. But your grandfather's come out to play." He pointed.

On the southern side of the Wall, Aetius had led his cohort out of the fortress and was drawing them up on parade. Aetius stood straight and tall, an example to his troops. But Regina understood how much effort that cost him, for at sixty-five years old he was plagued by arthritic pains.

The soldiers' helmets and shields gleamed in the sun, and most of them wore the chill, expressionless bronze parade masks that had so terrified her when she first saw them. But their lines were ragged, with many gaps, and Aetius, waving his arms with exasperation, called out the names of the missing: "Marinus! Paternus! Andoc! Mavilodo! . . ."

Regina knew how infuriating Aetius found such ill discipline and lack of professionalism. Aetius had once served with thecomitatensis forces, the highly mobile, well-equipped field army. Now he found himself the prefect of a cohort of thelimitaneus , the static border army, and things were very different.

These frontier troops had been on station here forgenerations . Indeed, nowadays most of them were drawn from the local people. According to Aetius, thelimitaneus troops had become thoroughly indolent, even immoral. He raged at their habit of bringing actors, acrobats, and wh.o.r.es into the fortress itself, and their tendency to drink and even sleep when on watch.

All this was cause for concern, to say the least. Without a meaningfulcomitatensis in the country, these ragtag troops were all that stood between civilized Britain and the barbarians. And it was up to Aetius to hold them together.

Aetius consulted a clay tablet and called out a name. One unfortunate trooper stepped forward, a burly, harmless-looking man who didn't look as if he could run a thousand paces, let alone fight off a barbarian horde.

"I was only drinking wine to wash down h.o.r.ehound to get rid of my cough, Prefect."

"Do we not treat you well? Do you not enjoy medical attention even the citizens of Londinium would not be able to obtain? And is this how you repay us, by dereliction of duty?"

Regina knew that Aetius's scolding was harder for the miscreant troopers to bear than the lashings that would follow. But now the fat soldier lifted up his arm and shook it, so his bronze purse rattled. "And is this how the Emperor repaysme ? When was the last timeyou were paid, Prefect?"

Aetius drew himself up. "You are paid in kind. The temporary lack of coin-"

"I must still buy my clothes and my weapons, and bribe that old fool Percennius to give somebody else the latrine duty." There was laughter at that. "And all for the privilege of waiting for a poke up the a.r.s.e from some Pict's wooden spear. Why do you think Paternus and the others have run off?"