*Oh, brother. You really don't get it, do you?' She was shaking her head, stabbing her finger on the table. *This is life. It's not a dress rehearsal. If we don't do this now, we may as well start planning our own funerals. I don't want to be sensible and prudent. Being sensible and prudent is for arseholes like Hector and Lucas. We turned away from all that, don't you realise? We wanted life, surprises, risk . . . not stocks and shares and tedious fucking boardroom meetings about the cost of importing ice from fucking . . . Neptune.' Realising that she was getting loud, drawing glances from across the restaurant, she dialled down her voice. *That's not the life for me, all right? Maybe you've changed your mind. I haven't. And if I have to find a way to get to Mars, I will.'

Geoffrey gave her his most infuriating calm-down nod. *All right. I get it. Really, I do. And although you may not believe me, I agree. But if we do this, we have to do it together. A shared risk. And we mustn't rush into it.'

*You've spent your whole life not rushing into things.'

He shrugged off the barb. *Maybe I have, Sunday, but I'm serious. If you insist on going to Mars, then I want to be part of that. She's my grandmother, too. But we do it on our own terms, without begging favours from anyone. The cousins promised to pay me pretty well for coming to the Moon, and there's more funding to follow. If I can find a way to channel some of that into a ticket to Mars . . . even two tickets . . . I will. But I'll need time to make it happen, and the last thing I want to do is give them even more reason to get suspicious.' He paused, absently picking at the edge of a wine bottle label. *If that means waiting months, even a year, so be it.'

*There's a favourable conjunction right now,' Sunday said. *Mars is never closer, the crossing never easier.'

*What goes around, comes around,' Geoffrey answered.

*Thank you. I think I have at least a basic grasp of orbital mechanics.'

Jitendra took her hand. *Maybe Geoffrey's right, you know? No one's saying we should forget all about this. But a year, two years . . . what difference will that make, given how long these clues must have been sitting around?'

Geoffrey nodded keenly. *Whatever we do, we shouldn't act right now. That'll be the worst possible thing, if we want to keep Hector and Lucas off our backs. Once I'm home I'll give them the glove, and in a few weeks they'll have forgotten all about it. Trust me on this a they don't have the imaginations to think further ahead than that. Not unless money's involved.'

*Let the trail go cold . . . then strike?' she asked.

*Exactly.' She sensed his pleasure and relief that she had come round to his way of thinking. *In the meantime, it'll give us all the opportunity to . . . think things over. We really don't know what we're getting into here. Today we escaped, but we were lucky, and we won't necessarily be lucky next time. We may think we know Eunice, but this could just as easily be her way of having a good laugh at our idiocy from beyond the grave. Or burial site.'

*She went to a lot of trouble to put that box under Pythagoras,' Sunday said. *Whatever was motivating her then, it wasn't just spite. And she won't be sending us to Mars out of spite either. She knows only family could get into that vault. She might want to test us, but she won't want to hurt us.'

*You hope,' Geoffrey said.

*I know this woman, brother. As well as anyone alive.'

And in that moment she felt more certain of that than anything else in the universe.

She woke in the middle of the night, Jitendra's form cool and blue-dappled next to hers. They had made love, when her brother was asleep in the next room, and then she had fallen into deep, dreamless oblivion until something caused her to stir. For once the world beyond her apartment was almost silent. Through the wall she heard Geoffrey snoring softly. From somewhere below, two or three stacks under her module, a shred of conversation reached her ears. Something clicked in the air circulator; there was a muted gurgle from the plumbing. From a block away came the shriek of a cat. A distant urban hum underpinning everything, like the engines in the basement of reality.

Sunday slid out of bed, mindful not to disturb Jitendra. Conscious that her brother might wake at any moment, she wrapped a patterned sheet around herself. She passed through the living room, through the clutter left over after their return from the restaurant. More wine, scarlet-stained glasses, bottles of beer. Chama and Gleb had come back to the apartment before returning to their own quarters. Though the conversation had hit some rapids, it had all ended cordially enough. They were friends, after all. In fact they had spent the rest of the evening trading musical instruments, Geoffrey turning out to be surprisingly nimble-fingered on her battered old kora, Chama astonishing them all by being able to bash out some desert blues on a dusty old acoustic guitar left in one corner of her studio by a former tenant. Then they had watched some cricket and drunk more wine, and the zookeepers had bidden them farewell, and not long after that Geoffrey had turned in, weary and anxious about his trip back to Earth.

From the clutter to her studio. She closed the door behind her and moved to the commissioned pieces, the slender white figures, the ones they now wanted redone in black. She stroked their hard-won contours, feeling the electric tingle of hours of accumulated work. The boundary between art and kitsch was negotiable, even porous. In the right setting, the right context, these pieces might have some questionable integrity. But she knew very well where they would end up, black or white: flanking the doorway to an ethnic restaurant that couldn't even be bothered to decide which part of Africa it was supposed to be parodying.

Indifference sharpened to hate. She hated the hours of her life this commission had robbed from her. She loathed it for the true art it had prevented her from creating. She despised it for the path it put her on for the future. She still liked to think she had ambition. Churning out emblematic crap for brainless clients was no part of that. It was easy to take one commission here, another there, just to pay the rent. Too much of that, though, and she might as well stop calling herself an artist.

In a moment of self-directed spite she raised her hand to smash the sculptures. But she stilled herself, not caring to wake Jitendra or Geoffrey.

That's you in a nutshell, she thought. You can't stand what you have to do to stay afloat, but you don't have the nerve to actually do anything about it. You do shit jobs to pay the rent, and you only get to eat in nice restaurants when Chama and Gleb are footing the bill. You're as much a prisoner of money as if you'd chosen to work for the family business after all. You just kid yourself that you've escaped. You might laugh at your brother, scold him for his unadventurousness. But at least he has his elephants.

In the morning they were up early to see him off, groggy-eyed and fog-headed from the night before. Geoffrey was tense about going back to Copetown, back to the Central African Bank. He had to do so, though. According to the current narrative, the glove was still in the vault. If he wasn't seen to return to the branch, his story would unravel at the first awkward question from the cousins.

*You'll do fine,' she told him.

He nodded, less convinced of this than she was. *I have to go into the vault, come out again. That's all. And the bank won't think this is funny behaviour?'

*It's none of their business, brother. Why should they care?'

They accompanied Geoffrey to the terminal, kissed him goodbye. She watched her brother speed back to the Surveilled World, and reflected on the lie she had just told him.

Because the last thing he had asked her was to promise that she wouldn't do anything rash.

CHAPTER EIGHT.

The thread-rider gobbled distance at an easy thousand kilometres per hour. They had put him under at the Copetown terminus but Geoffrey had exercised his right a and the cousins' expense account a to be revived when he was still three hours up from Libreville. Being revived prior to landing cost more than sleeping all the way a it required onboard medical support, as well as a recuperation lounge and space to stretch his legs a but he doubted that Hector and Lucas would begrudge him this one chance to see the scenery. After all, he had no idea if he would ever leave Earth again.

It was the afternoon of the twelfth of February. He'd only been on the Moon for six full days, but that was more than enough to make the transition to normal gravity thoroughly unpleasant. Some of his fellow passengers were striding around in full-body exos, worn either under their clothes a though they invariably showed through a or as external models, colour-coordinated with their underlying fashions. Geoffrey made do with slow-release drug patches, pasted onto his limbs. They sent chemical signals to his bones and muscles to accelerate the reconditioning, while simultaneously blocking the worst of the discomfort. He felt stiff, as if he had been exercising hard a day or two before, and he had to constantly watch his footing in case he stumbled. On the face of it, he was forced to admit, these were minor readaptive symptoms. Above all else, he was relieved it was over. There'd been no trouble at the Central African Bank. He'd returned to the vault, opened the drawer, closed it again. The glove remained in his holdall. Sunday had the jewels, and the pages torn from Eunice's book.

It was done. He could relax, take in the scenery.

The recuperation and observation deck was at the bottom of the slug-black cylinder, the single curving wraparound window angled down for optimum visibility. The other passengers were upstairs, on the restaurant and lounge level. Except for a woman who was studying the view a third of the way around the curve, Geoffrey had the observation level to himself.

Africa lay spread out before him in all its astonishing variegated vastness. The Libreville anchorpoint was actually a hundred kilometres south of its namesake city and as far west again, built out into the Atlantic. Looking straight down, he could see the grey scratch of the sea-battered artificial peninsula daggering from the Gabon coastline, with the anchorpoint a circular widening at its westerly end.

To the north, beginning to be pulled out of sight by the curvature of the Earth, lay the great, barely inhabited emptiness of Saharan Africa, from Mauritania to the Sudan. Tens of millions of people had lived there, until not much more than a century ago a enough to cram the densest megacity anywhere on the planet. Clustered around the tiny life-giving motes of oases and rivers, those millions had left the emptiness practically untouched. Daunting persistence had been required to make a living in those desert spaces, where appalling hardship was only ever a famine or drought away. But people had done so, successfully, for thousands of years. It was only the coming of the Anthropocene, the human-instigated climate shift of recent centuries, that had finally brought the Saharan depopulation. In mere lifetimes, the entire region had been subject to massive planned migration. Mali, Chad, Niger . . . these were political entities that still existed, but only in the most abstract and technical of senses, their borders still recorded, their GDPs still tracked. Almost no one actually lived in them, save a skeleton staff of AU caretakers and industrialists.

The rising sea levels of the twenty-first century had scarcely dented Africa's coastline, and much of what would have been lost to the oceans had been conserved by thousands of kilometres of walled defences, thrown up in haste and later buttressed and secured against further inundation. But there was no sense that Africa had been spared. The shifting of the monsoon had stolen the rains from one part and redistributed them elsewhere a parching the Congo, anointing the formerly arid sub-Saharan Sahel region from Guinea to Nigeria.

Change on that kind of scale, a literal redrawing of the map, could never be painless. There had been testing times, the Resource and Relocation years: almost the worst that people could bear. Yet these were Africans, used to that kind of thing. They had come through the grim tunnel of the nineteenth and twentieth centuries and made it out the other side. And at least climate change didn't ride into town with tanks and guns and machetes.

For the most part. It was pointless to pretend that there hadn't been outbreaks of local stupidity, micro-atrocities. Ethnic tensions, simmering for decades, had flared up at the least provocation. But that was the case the world over; it wasn't a uniquely African problem.

A million glints of sunlight spangled back at Geoffrey from the central Saharan energy belt. When people moved away, machines had arrived. In their wake they had left regimented arrays of solar collectors, ranks of photovoltaic cells and long, stately chains of solar towers, fed by sun-tracking mirrors as large as radio telescopes. The energy belt stretched for thousands of kilometres, from the Middle East out into the Atlantic, across the ocean to the Southern United States, and it wrapped humming superconducting tentacles around the rest of the planet, giving power to the dense new conurbations in Scandinavia, Greenland, Patagonia and Western Antarctica. Where there had been ice a hundred and fifty years ago, much was now green or the warm bruised grey of dense urban infrastructure. Half of the world's entire energy needs were supplied by Saharan sunlight, or had been until the fusion reactors began to shoulder the burden. By some measure, the energy belt was evidence of global calamity, the visible symptom of a debilitating planetary crisis. It was also, inarguably, something rather wonderful to behold.

*You see that patch there,' the woman said, having worked her way closer to Geoffrey. She was pointing at the Sudan/Eritrean coastline, the easterly margin of the Saharan energy belt. *That patch, a little north of Djibouti. That was the first grid to go online, back in fifty-nine. That's also where we sank the first deep-penetration geothermal taps.'

Geoffrey felt the need to be polite, but he hadn't been looking for a conversation. *I'm sorry?' he asked mildly.

*Our mirrors and taps, Geoffrey. The Akinya solar and geothermal projects.'

He looked at her with astonishment, taking in her face for the first time.

*What's going on?' he asked, lowering his voice to a hiss. *How are you here?'

*Oh, relax. I'm not here at all, really.' She looked peeved. *I'm obliged to tell you that, even though it's obviously not something I'd ever say in real life. Now can we move on?'

She was, now that he paid due attention, casting no shadow. And where her hand fell on the guard-rail around the window, the fingers blurred away.

*Not the answer I was looking for.'

*You can voke a I'll hear you well enough.' She turned away and stared out at the view for several seconds. *Look, it's very simple. Sunday authorised you to access a duplicate copy of me. She thought you might appreciate the companionship.' With the sweep of a hand she traced the indigo contour of the atmosphere as if it was the sweating flank of a racehorse. *Look at that planet. It's still beautiful. It's still ours, still our home. The oceans rose, the atmosphere warmed up, the weather went ape-shit, we had stupid, needless wars. And yet we still found a way to ride it out, to stay alive. To do more than just survive. To come out of all that and still feel like we have a home.'

*How are you just appearing in my head? I didn't authorise your figment.'

*Sunday had executive override authority because you're siblings, and when you were small you agreed to trust each other completely. Or did you forget that part?' She didn't wait for him to come back with a response. *The way I see things, it's all cyclic. Did you ever hear of the five-point-nine-kiloyear event?'

She didn't wait a beat for his answer.

*I thought not. It was an aridification episode, a great drying. Maybe it began in the oceans. It desiccated the Sahara; ended the Neolithic Subpluvial. Worldwide migration followed, forcing everyone to cram around river valleys from Central North Africa to the Nile Valley and start doing this thing we hadn't done before, called civilisation. That's when it really began: the emergence of state-led society, in the fourth millennium BC. Cities. Agriculture. Bureaucracy. And on the geologic timescale, that's yesterday. Everything that's followed, the whole of recorded history, every moment of it from Hannibal to Apollo, it's all just a consequence of that single forcing event. We got pushed to the riverbanks. We made cities. Invented paper and roads and the wheel. Built casinos on the Moon.'

*Sunday should have asked.'

*Take it up with Sunday. I didn't have any say in the matter.' Eunice moved around him to his other side, resting her hand on the rail again. *But this global climate shift, the Anthropocene warming a it's another forcing event, I think. Another trigger. We're just so close to the start of it, we can't really see the outcome yet.'

*You don't have any say in any matter, Eunice.'

*The warming was global, but Africa was one of the first places to really feel the impact of the changing weather patterns. The depopulation programmes, the forced migrations . . . we were in the absolute vanguard of all that. In some respects, it was the moment the Surveilled World drew its first hesitant breath. We saw the best and worst of what we were capable of, Geoffrey. The devils in us, and our better angels. The devils, mostly. Out of that time of crisis grew the global surveillance network, this invisible, omniscient god that never tires of watching over us, never tires of keeping us from doing harm to one another. Oh, it had been there in pieces before that, but this was the first time we devolved absolute authority to the Mechanism. And you know what? It wasn't the worst thing that ever happened to us. We're all living in a totalitarian state, but for the most part it's a benign, kindly dictatorship. It allows us to do most things except suffer accidents and commit crimes. And now the Surveilled World doesn't even end at the edge of space. It's a notion, a mode of existence, spreading out into the solar system at the same rate as the human expansion front. But these are still early days. A century, what's that? Do you think the effects of the five-point-nine-kilo-year event only took a hundred years to be felt? These things play out over much longer timescales than that. Nearly six thousand years of one type of complex, highly organised human society. Now a modal shift to something other. Complexity squared, or cubed. Where will we be in a thousand years, or six thousand?'

*Can I shut you up, or is that Sunday's prerogative as well?'

*You were raised with better manners than that.'

*Simple question: are you in my skull whether I want you there or not?'

*Of course not. I'm not even in your skull a I'm delocalised, running on the aug. You can always override the settings, tune me out. But why would you reject Sunday's gift?'

*Because I like being on my own.'

The figment sighed, as if it was quite beneath her dignity to speak of such things. *When you want me, I will be here. You only have to speak my name. When you don't want me, I will go away. It's as simple as that.'

*And you won't be watching the world through my eyes, when I think you're somewhere else?'

*That would be unconscionably rude. What I see and hear is only that which the environment permits. I won't be invading what little privacy you have left.'

*But you'll be talking to Sunday as well?'

*I am one copy; Sunday has another. We were the same until the instant we were duplicated, but I have now seen and experienced things that the other one hasn't . . . and vice versa, of course. Which makes us two different people, until we are consolidated.' She cocked an eye to the ceiling, heavenward. *Periodically, there's an exchange of memories and acquired characteristics. Remergence. We won't ever be quite the same, but we won't diverge too radically either.' She moved a hand closer to his, but refrained from touching. *Look, don't take me the wrong way, Geoffrey. I wasn't sent to torment you, or to make your life a misery. Sunday had the best of intentions.'

*I've heard that before.'

*You two are so very alike.' She returned her gaze to the window, a smile lingering on her face. In the time that Geoffrey had been standing on the observation deck, the thread-rider's relentless descent had brought the Earth closer. The horizon's curvature, though still pronounced, was not as sharp as when he had arrived at the observation window, and he could begin to discern surface features that had not been visible before. There, not too far from the anchorpoint, was the crisp white vee of a ship's wake a he could even make out the ship itself, where the white lines converged. It was probably the size of an ocean liner, but it looked like a speck of glitter. He could also distinguish smaller communities a towns, not just cities.

*It is beautiful, isn't it?' Eunice said. *Not just the world, but the fact that we're here, alive, able to see it.'

*One of us is.'

*I never thought I'd live to see the snows come back to Kilimanjaro. But things are improving, aren't they? Green returning to the desert. People reinhabiting cities we thought were abandoned for good. It won't ever be the same world I was born into. But it's not hell, either.'

*We shouldn't be ungrateful,' Geoffrey said. *If the world hadn't warmed, we wouldn't have made our fortune.'

*Oh, it's not that simple. Yes, we were there at the right time, with the right ideas. But we didn't just luck into it. We were clever and adaptable. It's not as if we depended on some drip-feed of human misery to make our happiness.'

It was true, he supposed a or at least, he was willing to let her believe it. Not that anyone could ever know for sure. You couldn't rewind the clock of the last hundred and fifty years, let the Earth run forward with different starting conditions. The Cho family had made their money with the self-assembling, self-renewing sea walls a prodigious, damlike structures that grew out of the sea itself, like a living reef. When the oceans had stopped rising, the same technologies enabled the Cho industrialists to diversify into submerged structures and mid-ocean floating city-states. They grew fabulous Byzantine marine palaces, spired and luminous and elegant, and they peopled them with beautiful mermaids and handsome mermen. They were the architects and artisans behind the aqualogies of the United Aquatic Nations.

The Akinyas had done well out of the catastrophe, too. Like elixir to an ailing man, their geothermal taps, solar mirror assemblies and lossless power lines had given the world the gigawatts it needed to come through the fever of the twenty-first century's worst convulsions. That artifice with deep-mantle engineering, precision mirror alignment and super-conducting physics had provided the basic skill set necessary to forge the Kilimanjaro blowpipe.

Accidents of geography and circumstance, Geoffrey thought. The Akinya and Cho lines had been bright and ambitious to begin with, but brightness and ambition weren't always sufficient. No matter what Eunice might think, blind luck and ruthlessness had both played their parts.

*I don't know if we have blood on our hands,' he said. *But I don't know if we're blameless either.'

*No one ever is.'

*Except you, of course. Sitting in judgement on the rest of the human species from your castle orbiting the Moon. Laughing at us from beyond the grave.'

Her voice turned stern. *Being dead isn't a laughing matter for anyone, Geoffrey. Least of all me.'

*So why did you do it?'

*Why did I do what, child?'

*Bury those things in Pythagoras.' He shook his head, maddened at his own supine willingness to accept this figment as a living, thinking being. *Oh, what's the point? I might as well interrogate a photograph. Set fire to it and demand it tells me the truth.'

*As I think Sunday made adequately clear, I cannot lie, or withhold information. But I also can't tell you anything I don't know.'

*So you're fucking useless, in other words.'

*I know a lot, Geoffrey. Sunday's packed a whole lifetime's worth of public scrutiny in me. And I'd tell you everything, if I could a but that would take another lifetime, and neither of us has quite that much time on our hands. Instead, we're just going to have to live with each other. If you have a specific query, I will do my best to answer. And if I have a specific observation that I think may be useful to you, I will do my best to provide it in a timely fashion.'

*You sound like there's a mind at work behind those eyes.'

*So do you.'

It was sleight of hand, of course. No conscious volition animated the Eunice construct, merely ingenious clockwork. Across a life's worth of captured responses, data gathered by posterity engines, there would be ample instances of conversational situations similar to this one, from which Eunice's actual, documented responses could be extracted and adapted as required. A parlour trick, then.

But, he had to admit, a dazzling one.

*Well, I merely wished to make my presence known,' Eunice said. *I'll take my leave of you now. I expect you have a lot on your mind.'

*One or two things.'

*It would be good to see the household again. You'll at least give me that satisfaction, won't you?'

He was being pleaded with by algorithms. *Provided you don't make a nuisance of yourself.'

*Thank you, Geoffrey. You've been tolerant. But then Sunday promised me you would be. I always did like you two the most, you realise. Out of all my children and grandchildren, you were the only ones who showed that rebellious spark.'

Geoffrey thought of all the times Eunice had bothered communicating with him, when she had been alive. If the construct's opinion was an accurate reflection of the real woman's feelings, she had done an excellent job of concealing them from the rest of the family. Orbiting above him, looking down from her Lunar exile, she had exuded about as much warmth as Pluto.

*You really made us feel appreciated,' he said.

It was a jolt to find himself out in the sunshine, back in Gabon, a free man returned to Earth.