And Brikanti had grown traditions of its own. This was no empire; it was a federation of nations, and a democracy, of sorts, with traditions inherited from both its British and Scandinavian forebears. That old fort on the hill was now the seat of the Althing, an assembly with representatives of Brikanti holdings around the world, and the most powerful single individual was not a hereditary emperor but an elected logsogumadr, a law-speaker.

But this was a world that had been industrialised for centuries, a process that had proceeded without conscience or compensation. So, even on a bright midsummer day like today, a pall of smog hung over the city. No trees survived in Eboraki, save in the carefully preserved oak groves. In this capital people dressed brightly, in embroidered cloaks over colourfully striped tunics and leggings, adorned with beads of blue glass or amber, and with torcs of steel or silver at their necks. But they routinely wore face masks and goggles to keep the muck out of their eyes and lungs, and life expectancy in a culture capable of sending ships to the planets was shockingly low. Nobody here, of course, could imagine things could be different. It was when Penny was least busy, when she walked in the city looking at the children coughing into their filthy masks, that she most acutely missed the world she had left behind.

And yet, as the months had passed, to walk these streets at the times of solstice, midsummer and midwinter, with the low sun of morning or evening suspended over the streets and filling the city with light, had pleased her in ways she would have found hard to describe.

The meals in the small refectory were prepared by students as part of their education, under the supervision of a few townspeople. The fare, served at rough-hewn wooden tables, was traditional Brikanti, meat-heavy, laden with butter and vegetable sauces and served with slabs of gritty bread – although Roman fare was also available, cheese, olives. Rice and potatoes were expensive foreign luxuries, even in the Brikanti capital. All the Tatania crew had had problems with this diet, mostly from a lack of roughage. But Penny had learned not to try to change some things, such as the Brikanti habit of serving meals, even to very young children, with watered-down mead or beer. Or the habit of eating your food with the knife you wore at your belt.

Still, the meat, a richly stewed beef, was tender and tasty, and for a while they ate without speaking.

At length Ari said, picking up the conversation where they’d left off, ‘You don’t need to thank me for visiting. For one thing it’s my job; I’m expected to report to the Navy funding body who provided the cash for all this. For another it’s a pleasure to see how you’re getting on. I sometimes feel as if I connect you all, the crew of the Tatania.’

‘We are all rather scattered,’ Penny admitted.

‘But that’s not a bad thing. It shows you’re finding places in a society that must be very strange to you. How’s Jiang, by the way?’

‘Doing fine. Our house is comfortable. You know that he is working at the college; he gives classes in kernel engineering, among other topics.’

‘I can understand he will be finding it a particular challenge here. We like to believe we are world citizens, we Brikanti. In fact it is very rare to see a Xin face, even here in Eboraki, the capital.’

Marie Golvin said, ‘Well, he wouldn’t call himself Xin, but the point’s taken. He doesn’t go out much.’

‘He’ll be fine,’ Penny assured her. ‘And so’s General McGregor, we hear.’

‘I saw him recently,’ Ari said. ‘Lecturing junior officers on the command and control techniques of your International Space Fleet.’ Through his smooth Brikanti, it was odd to hear him break into English. ‘He’s very impressive.’

‘He always has been. And I’ve known him since he was seventeen years old,’ Penny said, feeling a little wistful.

Ari watched her sharply. ‘That’s true in one of the reality strands you inhabited, so I hear. In the other—’

‘Yes, yes. In the other it was my twin sister who knew him – save she wasn’t a twin, for I didn’t exist at all. Whatever. I always knew Lex would land on his feet, wherever he ended up.’

‘You can see he wishes he could shed three decades and fly with the youngsters. To battle the Xin for the treasures of the Tears of Ymir!’

‘That sounds like Lex, all right. He’s visited us a few times. He’s most struck by the special relativity we teach here. In our reality, so he says, he always struggled with the maths. Here, you had no relativity theory. But you did have the kernels, and you discovered relativity experimentally, by driving your kernel ships up against the light barrier, and finding out the hard way that the clocks slow and the relativistic mass piles up.’

Marie said, ‘I heard of engineers being executed because they couldn’t make their ships travel faster than light.’

‘That was the Romans and the Xin, not us,’ Ari said. ‘And the stories are apocryphal anyhow.’

Penny mopped up her stew with her rubbery bread. ‘And Beth? How is your new wife, Ari?’

He smiled, but Penny sensed reserve. ‘Well, you understand that she is not formally my wife, since she had no family to give her away … She is fine.’

Penny and Marie shared a glance.

Marie said, ‘That’s all you have to say? How’s the baby? She’s overdue, isn’t she?’

He seemed to consider his words carefully. ‘We are dealing with the challenge of the birth in our own way.’

Penny frowned. ‘ “Challenge”? What’s challenging about it? Your medicine is pretty good when it comes to childbirth. I checked it over myself when Beth said she was pregnant, and I had Earthshine consult too. Her age would always be an issue, she is thirty-eight now … Why is this a challenge?’

‘This is a private matter,’ he said coldly, his pale face empty. Suddenly he had never seemed more alien to Penny, more foreign.

‘But—’

‘Instead, let us talk of Earthshine. Of your group it is he who has made the most dramatic entry into our society, as I’m sure you know. Even if his true nature is carefully kept a secret. As far as most people know he is simply another survivor of a ship of mysterious origin.

‘And he seems to be attempting superhuman feats. You must know that he is now at Höd.’ The Brikanti name for Ceres. ‘He intends, with the party of supporters he has gathered around him, to move on to Mars. In a way this fulfils the promise of the images he showed us when we first encountered you: the great buildings on the Mars of your reality. But here, he claims, he will achieve much more.’

Penny grunted. ‘I often thought he’d have made a great salesman. If only of himself.’

‘He intends—’ Ari mimed a shove with his upraised hand ‘—to push Höd out of its track around the sun, and make it sail to Mars.’ He looked at them. ‘This is what he claims. I have performed my own estimates of the problem, the energies required. Do you think this is achievable?’

Penny, startled, looked at Marie.

Marie said, ‘With a hefty enough booster, any such feat is possible. And this society is knee-deep in kernels, which have been used in ways we never dared … Yes, I would say it is possible.’

‘Earthshine claims he will do this to deliver to Mars raw materials which that planet lacks. Water, other compounds, some metals perhaps. He intends, he says, to rebuild Mars.’

Penny said to Marie in English, ‘Terraforming. I bet that’s what he means. These people have no conception of such schemes, since they don’t even have a word for “ecology”.’

Ari frowned. ‘I cannot understand what you are saying.’

‘I apologise,’ said Marie formally. ‘In our reality there were grand plans to remake Mars into a world like the Earth. Maybe other worlds too, Venus, Titan – umm, the largest moon of Augustus. But on Mars it would mean importing a lot of volatiles – the kind of stuff Ceres, Höd, is made of.’ She looked at Penny doubtfully. ‘I guess it could be made to work. If Ceres could be brought into Martian orbit—’