Nomi said, ‘At first I thought the Xeelee must have lit up some exotic super-drive and got out of here. But I was wrong. That thing must be half a kilometre down. How did it get there?’

‘I don’t think it did,’ Hama said. He turned away and peered at Jupiter. ‘I think Callisto moved, Nomi.’

‘What?’

‘It didn’t have to be far. Just a couple of kilometres. Just enough to swallow up the Xeelee craft.’

Nomi was staring at him. ‘That’s insane. Hama, what can move a moon?’

Why, a child could, Hama thought in awe. A child playing on a beach - if every grain on that beach is a slice in time. I see a line sketched in the dust, a history, smooth and complete. I pick out a grain with Callisto positioned just here. And I replace it with a grain in which Callisto is positioned just a little further over there. As easy, as wilful, as that.

No wonder the Xeelee are afraid.

A new shuddering began, deep and powerful.

‘Lethe,’ said Nomi. ‘What now?’

Hama shouted, ‘Not the Xeelee this time. Callisto spent four billion years settling into its slow waltz around Jupiter. Now I think it’s going to have to learn those lessons over again.’

‘Tides,’ Nomi growled.

‘It might be enough to melt the surface. Perhaps those cryptoendoliths will be wiped out after all, and the route to configuration space blocked. I wonder if the Xeelee planned it that way all along.’

He saw a grin spread across Nomi’s face. ‘We aren’t done yet.’ She pointed.

Hama turned. A new moon was rising over Callisto’s tight horizon. It was a moon of flesh and metal, and it bore a sigil, a blue-green tetrahedron, burned into its hide.

‘The Spline ship, by Lethe,’ Nomi said. She punched Hama’s arm. ‘Our Spline. So the story goes on for us, my friend.’

Hama glared down into the ice, at the Xeelee craft buried there. Yes, the story goes on, he thought. But we have introduced a virus into the software of the universe. And I wonder what eyes will be here to see, when that ship is finally freed from this tortured ice.

An orifice opened up in the Spline’s immense hide. A flitter squirted out and soared over Callisto’s ice, seeking a place to land.

Exhausted, disoriented, Callisto and her followers stumbled down the last length of trunk and collapsed to the ground.

She dug her good hand into the loose grains of reality dust. She felt a surge of pride, of achievement. This island, an island of a new possibility, was her island now.

Hers, perhaps, but not empty, she realised slowly. There was a newborn here: lost, bewildered, suddenly arrived. She saw his face smoothing over, working with anguish and doubt, as he forgot.

But when his gaze lit on her, he became animated.