All this was why, in fact, the castaways each had to be smart. Proxima was not only feeble, it was a star that flared and sputtered, and its light output was unpredictable. The castaways had to be able to adapt, to make optimal use of the uncertain light that reached them, gathering it to serve the cause, in the few seconds of their usefulness, before they were hurled away, spent.

Eventually only one would remain, one sister, to go into orbit around Proxima, with a tremendous array of nearly a million mirror-sisters stretched out across a volume of space before her – all of them doomed to fly on past Proxima and into the endless dark, all save the one delivered to orbit. It was a nightmarish design: to deliver just one mirror-sister, atom-thin, with the mass of a mist droplet, nearly a million sisters would have to be sacrificed. But it would work.

Angelia 5941 rejected the cruelty of it. But she could not stop it.

She promised herself that if she survived, somehow, if she was the one, she would reject the goals of those waiting patiently on Earth for news of her arrival. She would formulate her own, more appropriate goals. And she would seek out the one being who might have some understanding of what she had gone through.

She would find Dexter Cole.

CHAPTER 27

2173

As the Arduan day-years rolled by, as the Earth months ticked off on their calendars, they extended their fields bit by bit: churning up the Arduan ground, scraping off layers of native life from the surface and shovelling them into the ColU’s reactors to be broken down into feedstock, spreading the ColU’s newly minted soil over the surface. Soon they had grass growing alongside the potatoes, spindly wheat, even a couple of precious apple trees, for now just skinny saplings a long way from producing edible fruit.

They did some homesteading too. To replace their slowly disintegrating clothes they learned to make a kind of cloth, experimenting with fibres drawn from the bark of forest-fringe saplings; you could pull apart the fibres, beat them, weave them. Mardina was more creative, and she started experimenting with looms. She also made bark sandals, similar to a kind her people had once made from the bark of gum trees, she said, to give their feet a break from ISF-issue boots. Yuri contented himself with making coolie hats, crudely woven from strips of bark, but useful for keeping off Proxima’s light on the bad days. It was the kind of work that kept them busy in the hours they had to hide out in the storm shelter from the more violent flares.

You couldn’t call this a colony any more, if it ever had been, Yuri thought. Not with just two people, one farm robot, zero future. But he got some satisfaction from the work even so. He was building something, after all, something new, on the face of this world that had never known the tread of a human foot until a few years back. And it was something he had built, and that was another thing that was new in the universe. He was twenty-seven years old now. Everywhere else he’d ever lived had been built and owned by somebody else, on Earth, on Mars.

But to neither him nor Mardina, he suspected, would this ever feel like a home. It was a place where they were surviving, on this huge, static, empty world, with no sign of humanity anywhere, no movement save the pottering of the ColU, no sound but the alien noises of the local life, the flap of the kites over the forest canopy, the rustling of the builders by the lake. He and Mardina were as isolated on Per Ardua as Neil and Buzz in their lunar module on the lifeless moon.

The ColU seemed content, however. It whirred around busily, inspecting the native life close up, concocting elaborate theories about the solutions produced by billions of years of evolution to the problem of how to exploit the energies of Proxima’s light.

Yes, they kept busy. Yuri imagined that if they really were being watched by some corps of concealed ISF inspectors, as Mardina continued to seem to believe, they might be given good ratings for their progress.

But inside his head, out of sight of any unseen cameras, unheard by any hidden microphones, there were days when Yuri felt overwhelmed by a kind of black depression. Maybe it was the static nature of this world, the sky, the landscape, the stubbornly unmoving sun. Nothing changed, unless you made it change. Sometimes he thought that all the work they were doing was no more meaningful than the marks he used to scribble on the walls of solitary-confinement cells in Eden. And when they died, he supposed, it would all just erode away, and there would be no trace they had ever existed, here on Per Ardua.

He suspected Mardina felt the same, some of the time, maybe all of the time. He thought he could see it in the way she did her work, always competently, but sometimes with impatient stabs and muttered curses. He thought he could see it, the black cloud inside, even in the way she walked around the camp.

But they never spoke about it.

CHAPTER 28

About two years after Synge’s killing spree, on a clear, bright Sunday, Yuri and Mardina decided to take a walk to go and see the builders around the Puddle. They had developed a habit of putting aside Sunday, as marked by their calendars, as a rest day. And the native life was a distraction for all three of them, the ColU included.

So they pulled on their boots, and stuffed backpacks with filtered lake water and food, rain capes and coolie hats.

The ColU was cautious as it scrutinised the patterns of flaring on Proxima’s broad face this morning. Yuri knew it was trying to improve its predictions of flare weather. When it issued a warning Yuri and Mardina generally listened; it was right perhaps sixty per cent of the time. But this morning, though it spent a long time staring at the star, the ColU issued no such warning.

The ColU led them by a different trail than usual, longer, heading towards the landmark of the Cowpat, and passing other features, eroded bluffs of sandstone seamed by intrusions of granite or basalt. At one of these the ColU paused. It took samples in its grabber claws of rock, dirt, life forms, and pressed its pod of sensors against rock surfaces. It also had a drill like a mole that would burrow into the ground or beneath a rocky surface, moving independently, but trailing a fibre-optic cable to pass data back.

All this work disturbed a kite that had been sheltering behind the bluff; it flapped away irritably. There seemed to be at least one solitary species of kite that lived apart from the great flocks of the forests and the lakes, and nested in the shelter of isolated rock outcrops like these.

Mardina mused, watching the ColU work, ‘You look like a rover. On Mars or Titan. One of those rickety gadgets that they used to control from Earth. Crawling a few centimetres a day, year after year.’ She glanced at Yuri. ‘Maybe you remember them. Or saw them in the museums.’

Yuri shrugged.

‘The analogy is apt,’ the ColU said. ‘You could say that in some regards I am a remote descendant of such probes. I have an onboard analysis suite, including, for example, a mass spectrometer so that I can determine the isotopic composition of samples of air or rock or water solutes. I have also improvised an incubation chamber where I am attempting to grow samples of Arduan life in controlled conditions. In that regard I am imitating the Vikings, early probes that landed on Mars and—’

‘What’s the point?’ Yuri snapped. ‘You’ll never be able to report any of this.’

‘Earth will recontact Per Ardua one day, though not, as Major McGregor promised, for a century at least. I will long have been terminated before then. But there is no reason to believe the results of my investigations will not survive; I have a number of hardened stores, which if deposited beneath a cairn or some other suitable monument—’