‘Like Gemo Cana?’ Symat laughed. ‘Luru, there are no survivors from before the Occupation. The Qax withdrew AntiSenescence treatment for two centuries after the Occupation. All the old pharaohs died, before the Qax began to provide their own longevity treatments. These modern undead, like Gemo Cana, have been bought by the Qax, bought by the promise of long life.’ He leaned towards her. ‘As they are buying you, Luru Parz.’

They emerged from the clean blue calm of the facility, back into the grimy mire of the town.

Disturbed, disoriented, she said evenly, ‘Symat, the starbreaker beams are coming here. Once the Qax tolerated activities like this, indigenous cultural and scientific endeavours. Not any more, not since the Friends of Wigner betrayed the Qax’s cultural generosity towards indigenous ambitions.’ The Friends had used a cultural site to mask seditious activities. ‘If you don’t move out you will be killed.’

He clambered on a low wall and spread his arms, his long robe flapping in the thin dusty breeze. ‘Ah. Indigenous. I love that word.’

‘Symat, come home. There’s nothing here. The data cleansers were sent through this place long ago.’

‘Nothing? Look around you, Luru. Look at the scale of these old foundations. Once there was a host of immense buildings here, taller than the sky. And this roadway, where now we mine the old sewers for water, must have swarmed with traffic. Millions of people must have lived and worked here. It was a great city. And it was human, Luru. The data might have gone; we might never even know the true name of this place. But as long as these ruins are here we can imagine how it must once have been. If these last traces are destroyed the past can never be retrieved. And that’s what the Qax intend.

‘The Extirpation isn’t always a matter of clinical data deletion, you know. Sometimes the jasofts come here with their robots, and they simply burn and smash: books, paintings, artefacts. Perhaps if you saw that, you would understand. The Qax want to sever our roots - to obliterate our identity.’

She felt angry, threatened; she tried to strike back at him. ‘And is that what you’re seeking here? An identity from unravelling this piece of obscure physics?’

‘Oh, there is much more here than physics.’ He said softly, ‘Have you ever heard of Michael Poole? He was one of the first explorers of Sol system - long before the Occupation. And he found life, everywhere he looked.’

‘Life?’