Ari said, ‘One of the Romans’ most significant projects. And they are slowly succeeding in making the desert bloom, as you can see. But there is a danger that in years to come, as they advance their colonies ever further south—’

‘And the Xin work their way north from their southern farmlands,’ McGregor said, ‘they’re going to meet in the middle, and clash. It will be Central Asia all over again.’

‘Let us hope not,’ Ari said fervently. ‘But, yes, those of us druidh who devote their efforts to projections of the future see this as one possibility.’

‘Here’s South America,’ Penny said.

‘Or Valhalla Inferior,’ Ari said mildly. ‘A battleground between the Xin and the Romans for centuries.’

Beth saw farmland and mining country cut across by vast river systems, and scarred by swathes of desert. ‘What about Amazonia?’

Penny said drily, ‘You’d never know the rainforest had ever been there. And again, we’ll probably never know what happened to the indigenous populations.’

In North America, images taken in the dark of night showed a band of fire that Beth thought roughly followed the Canadian border with the United States.

Penny said, ‘The continent is relatively undeveloped. There’s a big city of some kind on the site of St Louis, another in Massachusetts. Other than that, small towns and army bases. There is what looks like a Roman legionary fortress on the site of downtown Seattle, for instance, where I grew up – I looked to see. And this is the only place on the surface of the Earth where it looks like there is active warfare in progress.’

Ari said, ‘This is an arena I know well – I have served here. We Scand reached this country first, more than a millennium ago, and then the Brikanti followed us – and the Romans, some using Scand ships, came soon after. Now, to the north is Brikanti country, once thickly forested, where we extracted wood for our ocean-going ships. Our principal city, near the east coast, is called Leifsholm. To the south, farmland developed by the Romans, a great breadbasket. Their own provincial capital, on the course of a mighty river, is called Messalia. We meet at the latitude of the inland seas. There are no great cities here. In a sense it is a question of tradition, of history. The old countries, Europa and Asia, are where you build cities, whether you are Xin or Roman or indeed Brikanti. The rest of the world is to be exploited.’

Penny said, ‘That border country looks like a war zone.’

‘So it is,’ Ari said. ‘The Romans like to send their legions marching north. We oppose them with fortresses and counter raids.’

‘I thought you guys cooperated. You run interstellar missions together, for instance.’

Ari shrugged. ‘We cooperate when we fly to the stars, while warring on Terra, in the Valhallas. It is a kind of game. Lethal, of course, but a game. The Romans give their legions marching practice and their generals triumphs. We, conversely, enjoy tripping them up. It is not logical, but when has the politics of empire ever been rational? We must retain our separate identities somehow, Penny Kalinski. And after all, the Romans did consider invading Pritanike once. You don’t forgive something like that.’

Penny shook her head. ‘A continent as one vast military training ground.’

‘But what else is such a barren continent good for?’

‘You’d be surprised,’ Penny said fervently.

McGregor said, ‘So, an endless three-way war, now extended out into the solar system.’

‘It has gone this way for centuries,’ Ari said. ‘It is our way, evidently—’

‘Giving away our strategic secrets, are you, druidh?’

Beth turned to see Kerys the trierarchus, the ship’s commander, walking into the cabin through the door at the rear. She was followed by a solid-looking Earthshine, an impressive display of virtual projection from the unit in which the old Core AI was stored.

Ari came to a kind of attention. ‘That wasn’t my intention, trierarchus. I believe that I have learned as much about the home of Beth Eden Jones and her companions as I have revealed about ours.’

Lex McGregor grinned. ‘And I bet that’s true, you slippery little rascal.’

Kerys walked to the window, hands clasped behind her back, and peered around, beyond the glowing surface of Earth, into space. ‘Well, our rivals cluster close. They wait on a decision on how we are to dispose of you, the crew of the Tatania. And, needless to say, my superiors at Dumnona have devolved the decision to me.’

Lex McGregor said evenly, ‘My heart aches for you.’

Kerys arched an eyebrow. ‘A fine way to talk to an officer who holds you dangling by the testicles.’

McGregor barked a laugh.

‘What am I to do with you yourself, for example, General Lex McGregor? Look at you, old and grey, your prime a distant memory. What possible use are you? I might throw you over to the Romans; you might make them laugh, briefly, if they dump you in the arena with a gladiator or two.’

McGregor grinned, fearless. ‘I’d like to see them try that. Madam, I would have thought my value is obvious. I come from an entirely different military tradition, an entirely different spacefaring background.’ He tapped his grizzled pate. ‘And now all that experience can be put at your command. But,’ he said severely, ‘I come with strings attached. I want my crew with me, Golvin, Kapur, the others – all five of them. Without them I could not function, and would not try. Conversely, throw even one of them to the Romans or the Xin and I will follow.’

‘Your loyalty is commendable,’ Kerys said, her face kept carefully blank. ‘You, Penelope Kalinski: frankly your value is obvious even to me. The philosophies and mathematics you display, the technologies you wield – if you spent your remaining years teaching Brikanti students even a fraction of what you know, you could be of immeasurable value.’

Penny nodded her head. She was composed, Beth thought, unmoved, as if she’d thought her way through this already. Penny said, ‘I can think of worse ways to spend my life. I would need Jiang with me, of course.’

‘We can debate that,’ Kerys said neutrally. ‘As for you, Beth Eden Jones—’

She stared closely at Beth, and Beth found herself touching the tattoo that sprawled over her face, a relic of her childhood on Per Ardua: a mark the Brikanti seemed to regard as savage.

‘I can vouch for her,’ Ari said quickly, forestalling whatever judgement Kerys was about to pronounce. ‘Trierarchus, she is in many ways the most interesting of all. She was born and grew up on the planet of another star! Embedded in a system of native life of which we have no knowledge – as you know, our ships found no such life on any planet of the star Proxima. She was brought back to Terra as a young adult, and as an outsider she is probably a better witness to that culture than any of these others. Again I cannot say precisely what I would learn from her, given time, but—’

‘All right, druidh,’ Kerys said, raising a hand. ‘You’ve made your point.’

‘Which leaves me,’ Earthshine said silkily.

‘Indeed. And you present the greatest challenge of all. The machinery that sustains you is impossibly far beyond our understanding – I would have no way of knowing if it represented some kind of danger to my country.’

‘Nor what its potential might be,’ Earthshine said, ‘if you were able to learn from it.’

‘Very well. But what of you?’ She walked around him, inspecting him; she passed a hand through his arm, making pixels scatter in the air, and Beth saw Earthshine flinch as his consistency protocols were violated. ‘What are you? Not a man. Are you any more than a puppet? Is there a mind in there?’

‘I have been accused of being insane,’ he said, smiling coldly. ‘Can one be insane without a mind? And let me remind you what I have stored, in my artificial mind, my roomy memory: the secrets of what made the Tatania fly. The hulk you captured is scrap metal. And I have all the records we brought with us of our reality, and everything we achieved there.’