*There's an odd undercurrent to that question,' the vast form retorted, with unmistakable menace.

*Suit yourself,' Geoffrey said. He was thinking of the girl at the scattering again, the figment that bore a striking resemblance to the younger Lin Wei. *This discovery,' he went on. *Shouldn't it be public knowledge?'

*Soon it will be. The discovery was made late last year, less than four months ago. We're still in the embargo phase, meaning that . . . at this point in time . . . there are probably fewer than a dozen people in the solar system currently privy to this data. All but one of them has an intimate connection with Ocular. You're the exception.'

Geoffrey wondered where all this was leading. *So what did you find?'

*I can't take any credit for the discovery. It was made by Ocular itself, or rather by Arachne, the controlling intelligence at the heart of the instrument. Arachne is an artilect a a very smart one, forged from the fruits of Eunice's lab. The Cognition Police know about Arachne, and technically she a it a is within their threshold of concern. But they've given the project a special dispensation. Arachne is a harmless orphan, floating in deep space, blind to the world except for what she sees through Ocular's own eyes. What she found was stupendous and world-shattering. That was why she brought it to my attention.'

The image had changed while Geoffrey's attention was distracted. It was still the same blue planet, but now the cloud cover had been scoured away, the blue-green marble polished back to oceans and ice and land masses.

*I'm not-' Geoffrey began.

*Let's zoom in,' Arethusa said, *down to an effective resolution of about three hundred metres. That's not enough to image fine-scale structure like roads or houses, but it's more than adequate to pick up geo-engineering, cities, deforestation, agricultural utilisation, even the wakes of large seagoing vessels. The area you're seeing now is about one thousand kilometres across, centred very precisely on the equator.'

Geoffrey stared at the thing Arethusa was showing him. It was obvious to his eyes that it had no business being there.

*Arachne called it Maximum Entropy Anomaly 563/912261. Obviously it needed a better name than that. That's why I decided to call it Mandala.'

*Man-da-la,' he repeated, stressing the syllables slowly. *It's a good name.'

*Yes.'

And he marvelled. If the malleable skin of Crucible a the very planetary crust a had been warm wax, and into the wax had been embossed the hard imprint of an imperial seal, a seal of great intricacy, the result might have been something like this Maximum Entropy Anomaly, this Mandala.

At its heart was a system of concentric circles, ripples frozen in the act of spreading, but that basic organisation was obscured within layers of additional geometric complexity. There were squares, triangles, smaller circles a some positioned at the middle of the main formation, others at some distance from the centre. There were spirals and sinusoids. There were ellipses and horsetails and comma-like formations. It was, as near as Geoffrey could judge, marvellously, hypnotically symmetrical, in both the vertical and horizontal planes.

*And this . . . thing a it couldn't be a mistake, something . . . I don't know, imprinted on the data by . . . what did you call her?'

*By Arachne? No. She's infallible. I've injected enough test patterns into the Ocular data stream to be certain that she's absolutely dependable. Of course, we ran even more exhaustive tests, and we'll have run many more by the time we go public with this. But there's no doubt a Mandala is real.'

*OK,' he said slowly, sensing that Arethusa's assessment of his intellectual worth might depend acutely on his next utterance. *It's real. And I see that it isn't natural. Nothing natural produced that, not in ten billion years. But do you know what it is?'

*To the best of my knowledge . . . a system of mirrored channels, cut into the planet's surface. Lined with something highly reflective, which is sometimes exposed and sometimes covered by water.'

*Sometimes?'

*Crucible has two large moons. Their tidal effects produce an ocean swell, or rather a pattern of ocean swells, which sometimes lead to the channels being inundated. Water isn't a good reflector, so the effect is very pronounced. Water races into the channels and fills them in a complicated fashion. In a similarly complicated fashion, the water drains or evaporates from the channels again, leaving the mirrors exposed once more. The pattern doesn't appear to be quite the same from cycle to cycle. Whether that is down to chance, or whether the system is running through iterations . . . computational state-changes . . . we can't know. Not until we have a much closer look.'

*Are there moving parts?'

*That's a good question, and the answer again is we don't know a our resolution isn't sufficient to discern that. But here's the thing: whether or not any part of Mandala moves, the entire thing must be self-renewing, or under constant repair. Whether it's ten thousand or ten million years old, it must repair itself. If we dug channels like that on our own Earth, even with the best materials currently at our disposal, do you imagine they'd last more than a few millennia without upkeep?'

*Maybe it's not even that old.'

*I very much doubt that it was built within the span of human history. Given the age of the galaxy, the ages of the other stars and planets . . . that would be an almighty coincidence, wouldn't it? That someone made this thing, and we just happened to evolve a civilisation and the means to detect it a cosmic eye-blink later?'

*You think it's a lot older.'

*Yes, but not hundreds of millions of years, either. Crucible has plate tectonics, like our own Earth. Land masses move around on her surface. We trace their interlocking coastlines and deduce where they once fitted together, like Africa and the Americas. No structure that large could endure plate movement without being deformed or destroyed. Mandala's geometric symmetry is as perfect as we can measure with our current methods. It can't be much older than tens of millions of years. Which, I admit, is still a cosmic eye-blink.'

Geoffrey felt as if he'd stepped off a mental cliff and was still falling. Wisely or not, he rejected any notion that Arethusa might be lying. This was real a or at least she believed it to be so. Ocular had found something of epochal significance, one of the two or three most important discoveries in the history of the human species, and he was in on it from almost the outset. Stupendous and world-shattering, Arethusa had called it. That, he was forced to admit, was no exaggeration.

This knowledge changed everything. Sooner or later the world would know, and from that moment on . . . every thought, every action, every desire and ambition would be indelibly coloured by this discovery. How could it be otherwise? There was another intelligence out there, close enough to touch. And even if they were now gone, then the mere existence of their handiwork was wonder enough to fundamentally change humanity's view of the universe.

Well, perhaps. The world had absorbed the dizzying lessons of modern science easily enough, hadn't it? Reality was a trick of cognition, an illusion woven by the brain. Beneath the apparently solid skin of the world lay a fizzing unreality of quantum mechanics, playing out on a warped and surreal Salvador Dali landscape. Ghost worlds peeled away from the present with every decision. The universe itself would one day simmer down to absolute entropic stasis, the absolute and literal end of time itself. No action, no memory of an action, no trace of a memory, could endure for ever. Every human deed, from the smallest kindness to the grandest artistic achievement, was ultimately pointless.

But it wasn't as if people went around thinking about that when they had lovers to meet, menus to choose from, birthdays to remember. The humdrum concerns of normal life trumped the miraculous every time. Eunice's death had been a seven-day wonder, and the same would be true of the Ocular discovery when it went public. Maybe a seven-month or seven-year wonder, Geoffrey thought charitably. But sooner or later it would be business as usual. Economies would rise and fall. Celebrities would come and go. There would be political scandals, even the occasional murder. And the knowledge that humanity was not alone in the universe would be as relevant to most as the knowledge that protons were built of quarks.

But still . . . That didn't mean it wasn't momentous, that it wasn't an awesome privilege to be one of the first to know.

Quite why Arethusa felt he deserved that privilege, or what he was expected to do for her in return, were entirely separate mysteries.

*Forgive my scepticism, but . . .' he ventured. *Are you absolutely certain that it can't be a naturally occurring phenomenon? I mean, think of anthills . . . beehives. They have structure, organisation, that might imply conscious intent. Even geological or chemical processes can create the illusion of design.'

*It's good that you have doubts, but I don't think you've considered all the options yet. This is an order of magnitude a no, make that two or three orders of magnitude more complex than anything nature is capable of. That's a planet like Earth, Geoffrey. Its weather and surface chemistry obey predictable rules. There's only one conclusion, which is that Mandala was made. It's artificial, and it was designed to be seen. The people . . . the beings . . . that did this a they'd have known exactly how visible they were. They'd have known that instruments like Ocular would be capable of viewing them from dozens of light-years away. And still they did this, knowing full well that another civilisation would be able to detect their handiwork. It was deliberate. It was made to be seen.'

*Like a calling card,' Geoffrey said.

*Or, perhaps, an invitation to keep away. A territorial marker. Maybe a helpful warning sign, like a radiation or biohazard symbol. I don't know. I've been thinking about this image for months and I still haven't got any further with it. Ocular will continue monitoring Crucible, and the signal-to-noise will improve . . . but there's a limit to what we can find out from here. We'll have to get closer.'

*You mean go there?'

*If it takes a thousand years, that's within our scope. Don't look so surprised, Geoffrey a I credited you with more imagination than that.'

He shivered, for it was uncomfortably like being spoken to by his grandmother.

*It takes months just to get to Jupiter.'

*But the Green Efflorescence already demands of us that we achieve the means to cross interstellar space. We are already on that path. If Crucible is the spur that brings that goal closer, so be it.'

*You said this discovery was made late last year.'

*That's correct.'

*That's also around the time my grandmother died.'

*And you're wondering if the . . . shock of it was what pushed her over the edge?'

Geoffrey doubted there was much in the universe capable of shocking his grandmother. *Or something,' he allowed.

*She was surprised, as you'd expect. Brim-full of questions. Probing, insightful questions. Sharp until the end, your grandmother. But once she'd absorbed the news, once she'd asked me enough to satisfy her curiosity, it was almost as if she decided to put the whole business out of her mind, as if it really wasn't that important, just something we'd been talking about to pass the time. As if the discovery of intelligence elsewhere in the universe was no more consequential than, say, the news that a mutual acquaintance of ours was dying of some very rare illness. I'd told her the most astonishing news imaginable, given her this secret known only to myself at that point, and she was amazed, and then merely interested, and ultimately nonplussed.' Arethusa paused. *That was when I started to wonder whether something had gone wrong in her head, after all those years of seclusion. Had she lost the capacity to be truly astounded, because nothing astounding had happened to her for so long? But how could anyone become that jaded?'

*Based on what I knew of her, everything you've just told me makes perfect sense. She was emotionally detached, cut off from the things that used to matter to her. I'm not sure she cared about anything by the end.'

*There's still the fact of her death happening so soon after my visit.'

*It could be a coincidence.'

*I'd agree if there'd been a single sign that she was in any way ailing, losing her grip on life.'

*You chinged up there. That means you were seeing whatever the proxy made you see. Maybe she was more unwell than she let on.'

*That's possible,' Arethusa allowed. *But even if she was ill, the timing still troubles me. I show her the images of Crucible, and a few weeks later she dies? After one hundred and thirty years of not dying?' A pause. Then: *You've been there, since she died? To the Winter Palace?'

*Not me. Just Memphis a I suppose you'd call him our retainer. Been with the family for years, and the only one of us who was still dealing with Eunice on a face-to-face basis, even though he's not an Akinya.'

*I should very much like to speak with Memphis. It sounds as if he knew her better than the rest of you.'

*Good luck getting much out of him. Memphis isn't exactly one to go blurting out secrets.'

*Because he has something to hide?'

Geoffrey laughed. *I doubt it. But Memphis was loyal to her when she was alive, and he's not going to suddenly change now that she's dead.'

*And you've already spoken to him about Eunice?'

*I've asked him this and that, but he's not one to betray a confidence. Whatever passed between them, I'm afraid it'll go to the grave with Memphis.'

*Unless you make your own independent enquiries.'

*I do have a life I'd quite like to be getting on with. I'm a scientist, not an expert in digging into private family affairs.'

*Surely you grasp that this is about more than just your family now, Geoffrey. You are right to point out that I only chinged to the Winter Palace. Given my circumstances, that was unavoidable. But you could visit in person, couldn't you?'

*It's a bit late for that.'

*I'm thinking of the things she may have left behind. Records, testimonies. An explanation for her death. You should go, while there's still a chance of doing so.'

*The Winter Palace has been up there for decades. It's not going anywhere soon.'

*On that matter, your family may have other ideas.'

Text appeared to the right of Crucible. For a moment the words hung there in Chinese, before his eyes supplied the visual translation layer.

It was a request for *disposal of abandoned asset'. The asset in question was an axially stabilised free-flying habitable structure, better known as the Winter Palace. The request came from Akinya Space, to the United Orbital Nations Circumlunar Space Traffic Administration.

It had been submitted on February 12.

The day he got back from the Moon. The day he handed the glove to the cousins.

*If I were you,' Arethusa said, *I wouldn't wait too long before taking a look up there. Of course, if you need any help with that, you know who to call.'

CHAPTER SEVENTEEN.

Even with her eyes cranked to maximum zoom, Sunday couldn't see the far end of the cable car's wire. It was braided spiderfibre, strung between pylons. A dust storm was curdling in from Crommelin's far rim and all she could presently see was the line, suspended like a conjuring trick before it vanished into a wall of billowing butterscotch.

The car, as big as eight container modules blocked together, had two floors, a lavish promenade deck and a small restaurant. At least a hundred people were milling around in it with room to spare. The golem wasn't on the car a unless it was wearing someone else's face, and the Pan intelligence suggested otherwise a but that didn't mean Sunday wasn't being watched, observed, scrutinised to the pore. Certainly there were golems and proxies aboard, and in all likelihood one or two warmbloods as well. Chinging struck Sunday as profoundly meaningless in contexts like this. The whole point of being in the cable car was physical proximity to the landscape. One could passive ching as close as one wished, but that wasn't the same as being here, suspended by a thread of spiderfibre. Or was she just being old-fashioned? She wondered what June Wing would have to say on the subject.

Jitendra came back from the other side of the observation deck carrying two coffees in a plastic tray. *We're getting much lower now,' he said excitedly. *The car's dropping down from the main cable a there must be winches in the trolley, so we can go up and down according to the terrain.'

Sunday accepted the coffee. *You can draw me a sketch of it later. I'm sure I'll find it riveting.'

*Aren't you enjoying this?'

*Would be, if I'd come to gawp at the scenery. As it happens, there are a couple of other things on my mind.'

Jitendra's good mood wasn't going to be shattered that easily. Sipping his coffee, he studied his fellow tourists with avid interest. *And you're sure this is the right car?'

*I just got on the first one that came in. That was what Holroyd told me to do. Said our guide would make their presence known eventually.'

*Fine. Nothing to do but wait and see, then, is there?'

The scenery, she had to admit, was something. No, she hadn't come to play tourist a but she had come to play at being tourist, and the two were only a whisker apart.

In Crommelin, billions of years of ancient and secret Martian history had been flensed open for inspection, naked to the sky. Over time, over unimaginable and dreary Noachian ages, wind and water had laid down layers of sedimentary rock, one on top of the other, deposition after deposition, until they formed immense and ancient strata, as dusty and forbidding as the pages of some long-unopened history book. Crommelin's interior a wide enough to swallow Nairobi or Lagos whole a was a mosaic of these sedimentary layers. Here, though, something remarkable and fortuitous had happened. Not so long ago a aeons in human terms, a mere Martian eye-blink a an asteroid or shard of comet had rammed into the ground, drilling down through Crommelin's layers.

The impactor, whatever it had been, had made stark and visible the sedimentary deposits, exposing them as a grand series of horizontal steps, dozens upon dozens in height. Awesome and patient weathering processes had toiled on this scene to produce a landscape of alien strangeness. Flat-topped mesas, pyramids and sphinxlike formations rose from a dark floor, tiered sides contoured in neat horizontal steps as if they'd been laser-cut from mile-thick plywood. Some of the formations were bony, making Sunday imagine the calcified vertebrae of colossal dead monsters, half-swallowed into the Martian crust.

Others had the random, swirling complexity of partly stirred coffee, or caramel syrup in vanilla or pecan ice cream. It was gorgeous, moving, seductive. But like everywhere else on Mars, it was also both deadly and dead.

The cable car dipped again a Sunday felt the descent this time as its suspending line spooled out a little more a and they sailed over the edge of a tawny cliff as high as any building in the Zone. Her stomach did a little butterfly flutter. Tiny bright-green and yellow multilimbed robots clung to the cliff's side, glued like geckos. She voked a scale-grid. Actually, they weren't tiny at all, but as large as bulldozers. Not rock climbers, or even ching proxies, she was given to understand, but scientific machines, still conducting sampling operations.

The cable car rose and dipped again, clearing a long stepped ridge. Another line came in from the north-east, intersecting theirs at an angle. Sunday watched as a car on the other line lowered down to a railinged platform buttressed off the side of one of the rock formations. A handful of suited figures were waiting on the platform to board; others got off the cable car and began to follow a meandering metal path bolted to the cliffside. The cable car climbed away, reeling in its line to gain height, and soon it was lost in the butterscotch dust.

A sharp voice asked, *Sunday Akinya?'

The voice belonged to a proxy, a brass-coloured robot chassis with many gears and ratchets ticking and whirring in the open cage of its skull. Its eyes were like museum-piece telescopes, goggling out of its dialled face.

*Of course,' she said. *Since you're obviously not Holroyd, I'm guessing you're our guide?'

Sunday was alone. Jitendra had wandered off to use one of the swivel-mounted binoculars situated around the promenade deck.

*Gribelin will meet you in Vishniac. He knows the Evolvarium. He's already been very well paid, so don't let him talk you into any extra fees. Here are your train tickets.'

The proxy offered her its hand to shake and Sunday slipped her hand into its brass grip. The ruby-nailed fingers tightened. An icon appeared in her left visual field, signifying that she was now in possession of the relevant documents. Two seats, a private compartment on the overnight bullet from Crommelin to Vishniac, leaving tomorrow.

*This Gribelin doesn't sound very trustworthy.'

*Gribelin's mercenary, but he's also dependable. There's a coffee bar in the public concourse at Vishniac a he will be waiting for you.'

Sunday studied the bind tag. The proxy was being chinged from Shalbatana, but with the Pans' expertise in manipulating quangle paths that meant little.