Sigismund moved aside, bowing his head, waiting for his father to speak. The primarch did not look at him, and did not speak, but kept his eyes on the light of Terra.

Su-Kassen looked about her at the ruin of the command deck. Imperial Fists, servitors and tech-priests moved around her, securing the damaged bridge and repairing it as best they could. The dead had gone, but their blood remained.

‘Transmit the signals as soon as we are clear of the primary battle sphere,’ she said, to salutes and words of acknowledgement.

She looked around as one of the sets of holo-projectors activated and cast a sheet of blue light across the air. It was an enhanced image from visual sensors, a view of Terra alone against a field of stars.

‘Go,’ Rogal Dorn had said to her. ‘It is as we talked of, admiral. The battle will blood the earth now, not the void, but there is still a war to fight, out there to the edge of the sun’s circle. And the burden of that fight I must place on you.’

‘Lord Dorn, this is the ship of your Legion,’ she had said.

‘And the flagship of your command now, admiral.’ And he had nodded once, his eyes unblinking. ‘It was always going to be like this. No matter what else we planned, or designed.’ He had placed a hand on her shoulder. The golden digits felt heavy. ‘You know what is needed, and when to return.’

‘Yes, Lord Praetorian.’

‘Admiral,’ said a signal officer, ‘we are picking up a signal in reply to our broadcast.’

‘It is authentic?’

‘The code ciphers match those agreed by the contingency protocols,’ said the officer. ‘It is a ship of the Fifth Legion.’

She nodded to herself. It was a beginning.

Darkness rolled through the light of the sun. Ships came from the rift cut into the skin of space without cease: ships touched by the warp and the hands of the Dark Gods, vessels of war and exploration now become cathedrals of iron weeping cries into the night.

In his throne room, Horus stood before the grand viewport set behind his throne and looked out at the void. He saw as the last survivors of Camba Diaz’s fleet pulled away from Mars. He saw as the great slab-ships descended to the surface of the Red Planet, Hal’s nine prime disciples, Nul to Oct, kneeling in the dust before the Fabricator General.