And suddenly there was ambiguity. The potential futures multiplied around the word us. In one branch, Sanguinius meant himself and Curze. In another, he meant the triumvirate. The futures divided, splitting again and again before rejoining at critical junctures. Death was the constant. It drew the strands together. But a fog of potential lingered around it.

‘I don’t know what is on the surface,’ Curze said. ‘How could I? I didn’t even know we were at Davin until just now.’ He did not expect to have that knowledge. His certainties were centred around his end, and the immediate moment. No, he would never expect to know what was on Davin. Yet the fact he didn’t bothered him. His ignorance was a reminder of the earlier blankness. There was no reason to connect the two, yet he felt the link, and unease wormed its way into his veins again. His lips pressed together, turning his smile into a grimace. This was not the way of things. He was the Night Haunter. He was the bringer of nightmares, the murderer of sleep. Unease was his to bestow, not his to suffer.

‘I believe fate is down there,’ Sanguinius said.

‘Whose? Yours or mine?’

‘Horus’ was.’

‘You didn’t answer my question.’

‘I think it might be fate itself.’

Curze saw himself answer before he did. The inevitability of his words made them true, though he did not know why. ‘I think you’re right,’ he said. Truth and uncertainty collided. The unease grew.

Sanguinius cocked his head, listening to something on his vox-bead. His eyes hardened. ‘Roboute is returning to the Samothrace,’ he said.

‘I can see this concerns you.’

‘The Lion plans to bombard Davin with cyclonic torpedoes.’

Again the import of the words registered with Curze before they were said. The unease reached a point of crisis. The future rushed in, blazing at a point of critical disjuncture. Sanguinius stood on the surface of Davin in one branch. In another, the planet flew apart under the Lion’s bombardment. There was another branch, too, murkier, far more uncertain, hovering on the edge of potential. It blurred the future’s divide. It made both possibilities true.

‘Why have you come to free me?’ Curze asked. That Sanguinius was going to take him from the cell had suddenly become imminent, turning into a concrete inevitability in the last few seconds. Sanguinius’ reasons remained beyond his reach as they flickered and changed in microseconds, caught in the tempest of the Angel’s uncertainty.

A klaxon began to sound. The doubts lifted from Sanguinius’ face. His eyes hardened with determination. ‘Don’t you know?’ he said. ‘Because you do not die on Davin. And neither do I.’

Sanguinius left the cell. He turned to the guards standing a few yards down. ‘I am taking the prisoner with me,’ he said. ‘Prepare him for transport.’