Beth even lit a small fire and began brewing tea: tea she had gathered herself, she said, from a plant she’d found growing wild here, brewing in a clay pot she’d cast herself.

‘Always takes a while to boil in an open bowl,’ she said apologetically.

Nobody objected. The group was very quiet, in fact, gathered by the unnecessary warmth of the fire, as they waited for the tea.

Stef glanced around at her unlikely companions, relics of multiple collapsed histories, participating in what she supposed was a kind of welcoming ceremony. Titus Valerius sat with his daughter, who leaned against his muscular bare legs. Titus himself looked restless, baffled, oddly resentful, like a bull in a cage, Stef thought. Maybe he was still sulking from missing out on the battle at the habitat hub.

And Clodia was staring with obvious hostility at Mardina, who was rubbing some kind of ointment into the bare shoulders of Chu Yuen. The former slave had taken his shirt off, and Stef could see how his shoulders and chest had been chafed by friction from the heavy pack that bore the ColU. Stef, already thinking ahead to how they would survive here in the days and weeks to come, made a mental note that the ointment, whatever it was, wouldn’t last for ever. But they had the ColU, she reminded herself, which for now sat on a rock of its own, liberated from its customary backpack, interior lights gleaming. The ColU was a machine specifically designed to survive in the conditions of Per Ardua, and would no doubt be full of recipes for such things as skin ointments …

But Stef’s old-lady maundering at this moment was missing the point, she realised, the central theme of the little scene. After their adventure at Hanan Cuzco both the girls had been glad to be reunited with Chu Yuen – but of course there was more to it than that. Chu was the only young man here – perhaps in all this world – and Mardina and Clodia were the only young women, though Clodia was a few years younger. Mardina seemed close to Chu, but Stef had no idea if there was a genuine relationship there. Anyhow, what you had here was a Chinese Adam – and two Eves.

Oddly, Stef recalled, it was not unlike the scheme the ISF and its controlling UN agencies had drawn up for the original colonisation of Per Ardua, in a different reality: to seed the planet with apparently impossibly small groups, a dozen people each or so, screened for genetic diversity, and let them work it out. Beth herself was a survivor of all that. In the end the colonists had found their own way, basically by abandoning the ISF plan and congregating at the substellar. But they had left behind a trail of blood and lust and jealousy. Trouble ahead, Stef thought, just from the difficult triangle of these youngsters alone.

And then there were Inguill and Ari Guthfrithson, sitting side by side on the far side of the fire, not speaking, looking around at the group, at Beth’s improvised homestead – at the forest, the tall shafts of Per Arduan stem trees, presumably the most alien life form either of them had seen before. Beth, who had never visited the Inca Culture, was astonished by the sight of this woman in her cloak of hummingbird feathers. Inguill, looking around greedily at this new world, would say only through the ColU’s translation interface that she was here to extend the glory of the Sapa Inca.

What did the future hold for those two, Inguill and Ari? They were both scholars, both highly intelligent and manipulative people. They had both, in their separate histories, more or less deduced the existence of alternate realities from the accounts of jonbar-hinge survivors, if not from scraps of evidence they’d turned up themselves. Stef wondered how they felt now that their questing had brought them to this strange, sparse, distant, unexpected place. Watching them, she realised she really had no clear idea what they were thinking – what they were scheming. Penny seemed to have been suspicious too; she had restrained Ari from following Earthshine through the Hatch on that other Mars. It was a strange thought that Stef probably had less in common with them, two fellow humans, than with the ColU: a mind calm, analytical – and loyal.

Loyal, yes. And that reflection made her realise that once again she was missing a central point. Ari, Beth, Mardina were father, mother and daughter. And yet they had barely acknowledged each other, after the initial moments of shock as the group had emerged from the Hatch and the family was reunited. Even now, sitting in this little circle around the fire, they could scarcely be further apart. Not to mention Earthshine, who was Beth’s grandfather in some sense, off on the other side of the planet.

‘Families,’ she muttered. She caught Beth looking at her with a grin. ‘Sorry. Did I say that out loud?’

‘At least you broke the silence,’ Beth said.

‘Perhaps we’re all in some kind of state of shock. This has been a peculiar … journey. It’s difficult to know what to say.’

Beth nodded. ‘Well, then, just say what you feel. You, at least, have been here before, Stef. As I have. And indeed the ColU.’

The colonisation unit sat silently, inner lights winking.

Beth pressed, ‘You know I’m right, don’t you? Earthshine wouldn’t accept it. But you know this is Per Ardua. You knew it from the minute you walked through that Hatch – as I did, months back. I could see it in your face.’

Stef looked out at the world, the mix of muddy Arduan green-brown with the more brilliant splashes of Earth life – the vertical shadows that were appearing now that the rain was stopping, and the clouds above were clearing from the face of the overhead star. ‘Yes,’ she admitted. ‘I spent enough of my own life here. I think I could even sense it in the gravity, that slight, peculiar lightness you feel, like nowhere else I ever walked. Of course it’s Per Ardua. But it’s different, right? No traces of the human structures that used to be here – this was the UN’s administrative centre, after all, and a pretty well-developed city grew up here. But then we don’t know what timeline we’re in now, what became of Earth and Per Ardua—’

‘People got here,’ Beth pointed out. ‘From whatever version of Earth. They must have. Otherwise no tea.’

‘Or, strictly speaking,’ the ColU said now, ‘no heavily evolved wild descendant of a tea plant.’

Stef said carefully, ‘So the evidence of my senses tells me – yes, this is Per Ardua. But the differences are significant.’ She glanced up, at the pale image of Proxima that, as the clouds cleared, was beginning to shine through the fabric of the shelter-canopy. ‘Even the star seems different, somehow, subtly. My senses, my perception of the world, say one thing. But my head tells me that this isn’t the Per Ardua I know. Not quite.’

Titus Valerius grunted, and took an angry, impatient swig of water from a flask dangling from his heavy belt. ‘You talk of abstractions. This world is one thing or another, it is what you remember from before, it is not. What does it matter? We are here, now, in this place.’ He glanced around at the group, at their pitifully small pile of equipment, Beth’s and the Romans’. ‘Our hands and hearts and muscles, and the resources we find around us. That is all we have. That is all that matters. And,’ he said pointedly, looking at Beth, ‘those we share this world with.’

Beth sighed. ‘And we are all there is. Look, I can’t prove that we’re alone here. I haven’t explored every square kilometre of the planet. But while Earthshine was here we did do some exploring, and I walked a good way off to the south-east when he began his trek to the antistellar. I didn’t see anybody else, or any traces of their works. Nothing but the bedrock structures we found buried under the dirt here.’ She’d shown them the sonar images on her slate. ‘I’m ready to be proved wrong. But I don’t believe there’s another human soul on this world – nobody save Earthshine, wherever he is now.’