He stepped out of the shadow and into direct sunlight, the first sunlight on his face for many days. He turned, hand raised. The Wall was silhouetted. He saw complex sculptures cut into the upper surface – docks, he realised, quays and piers cut into the growstone and now stranded far above the water level. And above that the light towers stood proud, blind, and the great heads of dead Annids looked out at a frozen sea. The cold was bitter. Crimm pulled the flimsy blanket tighter around his body.

The man on the ice was, of course, Ayto. He held a hand up when Crimm’s creaking footsteps got too close. He didn’t move, didn’t so much as look around. Crimm waited obediently.

A pale shadow passed through the water.

When it had gone, Ayto relaxed. ‘Ah, you scared him off.’

‘You might have come back. We’re choking in there.’

Ayto glanced around. ‘And you might have put a coat on, you’ll freeze.’

‘This is the ocean side of the Wall.’

‘Obviously.’

‘It’s all exposed. The sea can’t be much higher than the level of the land on the other side.’ Crimm found it hard to think that through; the fresh air was making him groggy. ‘How did the sea get so low? Ah. Because all the water is heaped up as ice on the land.’

‘Just think, these are stretches of the Wall’s face nobody’s seen for generations.’

‘What do you think we should do? With everybody in the cistern, I mean. The vents are blocked. We can’t really stay there if that’s going to happen.’

Ayto looked around and sniffed the cold air. Crimm saw there was frost on his roughly cut beard. ‘Bring them out here. Or at least, find somewhere in the Wall closer to the ocean face.’

‘Why?’

‘Because we can find food here.’ He patted his dead seal. ‘Seal, fish. Maybe other animals.’ He glanced at the sky. ‘Spring’s coming, it must be, but the winter’s not done with us yet. Maybe it never will be. If the ice doesn’t clear, we won’t be able to use the wetlands, the forests. But out here . . .’

‘The Coldlanders survive, and it’s always winter where they live.’

‘That it is. Maybe folk from the other Districts will find a way out too, if any of them live through the sorting-out. Let them. But they can stay away from here; this is our bit of coast.’ He looked around, at sea, ice, sky. ‘Different way of living, this will be. Makes you feel different just to think about it, doesn’t it?’ He glanced up at the Wall. ‘That’s all gone now.’

‘Civilisation?’