Earthshine remained seated, while Stef and Penny stood and looked around. They were in a graveyard, set in the grounds of a small country church, evidently very old. The graves in their rows were topped by weathered stones, and some by more modern virtual memorials, nodding flowers or dancing figures or scraps of wedding albums or baby photos, sustained by the energies of the generous sunlight.

‘We’re not far from Paris,’ Earthshine said. ‘I mean, that’s where the source of this projection is. Once you would have seen the city smog as a smear in the sky, off to the north. Long gone now. The simulation is based on a live feed, incidentally.’

‘I recognise this place,’ Penny said. ‘We came here when Dad was buried.’

‘I came here alone,’ Stef said.

‘Whatever. He wanted to be buried beside Mom.’

Earthshine said, ‘Who in turn was buried beside her own mother. Your grandmother was a Parisian, and so here we are . . . I am drawn to graveyards, you know. Fascinating, poignant places. The evidence of human mortality, which I do not share—’

‘Even though you were once human,’ Penny said.

That surprised Stef. ‘What are you talking about?’

Penny smiled ruefully. ‘Since we got this summons, while you have been researching me, I’ve been researching our host . . .’

It was another outcome of the Heroic Generation age, she said. ‘Earthshine is actually the youngest of the Core AIs. Already his brothers were strong. They were useful for supporting the big post-Jolt projects: global in scope, very long term. But there was concern that the AIs, being non-human after all and running on an entirely different substrate, would not share humanity’s concern for its own well-being, and would pursue different agendas. So a new approach to emulating human-level AI was tried out. Volunteers were sought – or rather, the hyper-rich of the Heroic Generation competed for places—’

‘I was a Green Brain experiment,’ Earthshine said. ‘Major Kalinski, I was reverse-engineered as an AI. My name is – was – Robert Braemann. I grew up in North Britain, as it is known now. They opened up my head and modelled the hundred billion neurones, the quadrillion synapses, in a vast software suite that was itself state-of-the-art. It was done by nanoprobes crawling through my skull, multiplying, reporting . . . I was brought back to consciousness repeatedly, to monitor the process. I, I, felt nothing.’

Stef frowned. ‘They modelled every organic bit of you, or the essence of you. And you still claim to be you – whoever you were?’

Penny smiled. ‘Sis, you’ve put your finger on the paradox that troubles most of us, when you look at a Green Brain.’

‘Don’t call me “sis”.’

‘I considered calling myself Theseus. I doubt you’ve had time to read any Plutarch along with your quantum theory, Major. Theseus’s Paradox is this: Theseus’s ship had each of its component parts, the wood and the nails, replaced one by one, until the whole fabric was new. Is it the same ship? It is an old quandary.’

Stef thought it over. ‘If you define the ship by its function, it’s still the same ship. Or if you consider it as an object with an extension in time as well as space—’

‘Yes. Quite so. There are different cultural responses to the paradox, interestingly. The Japanese, for example, in their unstable country, used to build their temples of wood, that could be regularly and readily rebuilt – yet the temple stays the same.’ He smiled. ‘I had Japanese engineers manage my transition. While I lay there with my head opened up like a bucket of ice cream, I did not want my doctors to be paralysed by epistemological doubt.’

‘Yes,’ Penny said. ‘But in fact they didn’t just pour out one brain to make you, did they, Earthshine? Stef, he had nine donors. Nine parents. Think of that! So much for the Green Brain effort; all it gave us was a better interface to their inhumanity. Earthshine and his buddies plan for the long term, which is a good thing. But their vision of the long term is one that benefits them, ultimately, snug in their bunkers—’

‘I did not bring you here to argue over the justification for my own existence,’ Earthshine said. ‘I can only assure you that whatever you think of me, on some level I remain human enough to sympathise with how you must feel at a moment like this.’ He pointed. ‘Your father’s grave is just over there.’

They found it easily, only a few years old, a modest memorial beside the decades-old grave of their mother.

Penny said, ‘Weird for both of us, right? We supported each other, that day.’

‘No,’ Stef said. She turned away from her sister.

Earthshine stood now – the three chairs, empty, winked out of existence behind him – and he walked across to join them.

Stef said, ‘Earthshine, tell me what we’re supposed to see here.’

‘No,’ Penny snapped. ‘First, tell us what it is you want of us.’

‘I want you to be my allies,’ Earthshine said simply.

‘Because?’

‘Because he’s afraid,’ Stef said. ‘He told us that. But afraid of what?’

‘Of all this.’ He waved a hand. ‘As you remarked, we AIs differ from you humans – even I, more like you than my siblings – in that we think on long timescales. That is a distinction. And on the longest of timescales, what is there not to fear? We are motes, our very worlds are motes, floating in a universe that was born of unimaginable violence. Our little corner of the universe is tranquil enough now, relatively. But it was not always this way, and why should it remain so? What if our world, the universe itself, is destined to die in violence too, die of ice or fire? That would at least have a certain symmetry to the telling, wouldn’t it?

‘And what if we bring that violence down on ourselves? War is the wolf that has stalked mankind since before our ancestors left the trees. Though it’s largely gone unnoticed, my Core brothers and I have been working hard, mainly by influencing human agencies like the UN and the governing councils of the Chinese Greater Economic Framework, to bind up the wolf of war with treaties, with words. And we’ve largely succeeded, so far. Well, the fact that we stand here in the simulated sunshine having this conversation is proof of that. But now we are an interplanetary civilisation. That wolf, if it got loose now, if it got a chance, could smash whole worlds – it could have done that even before we stumbled across these kernels of yours . . .

‘But the kernels exist, and now we have a new factor to deal with – a new randomness. This strange discovery at the heart of the solar system, the kernels, this Hatch that leads nowhere – nowhere but to this, a raggedly changed reality. What power implanted the kernels and created the Hatch? What power is now meddling with our history? Who is it? What does it want? How can we deal with it? The very existence of these alien toys is destabilising – surely you can see that? And the more we discover of their power, the more destabilising they become.’

Stef said, ‘You want us to work with you.’

‘I need allies,’ Earthshine said. ‘We do, the three of us in the Core. Human allies. You have kept kernel physics from us; perhaps that is wise. Our priority now is to prevent these new discoveries sparking a devastating war. And if it turns out that the Hatch-makers really do have the power to meddle with our history . . .’

Penny asked, a little wildly, ‘And you brought us here because you have proof of that?’

He pointed. ‘Look at your mother’s headstone. Can you read French? Let me translate. Here lies Juliette Pontoin, born – well, you know the dates – accomplished chemist, wife to George Kalinski, beloved mother of Stephanie Penelope Kalinski . . .’

Mother of Stephanie Penelope Kalinski. Not of Stephanie Karen and Penelope Dianne. One name only. One true name.