The Lion opened a fleet-wide vox-channel, and heard the same command echoing and re-echoing. It was too late to attempt to reverse away from the fortress. But the ships might yet avoid disaster by taking the momentum into a turn, moving parallel to the barrier using a slingshot manoeuvre to break the wall’s grip. The Lion shifted his attention back and forth between the monster growing larger in the oculus, and the trajectory screens for the combined fleets. The lines were shifting, slowly. The fortress was coming closer, quickly. The prow of the Reason shuddered before the Lion’s gaze, mile upon mile of gothic majesty wrenched by forces that reduced it to insignificance.

‘Hails from the Red Tear and the Samothrace,’ said the vox-officer.

‘Private channel,’ the Lion said. His brothers wished to speak to him. As he had expected they would.

‘Where have you brought us?’ Guilliman demanded.

‘I don’t know, Roboute.’

‘Neither do I. We can’t identify the system, whatever it once was.’

‘If this is a system, it has been moved,’ Sanguinius said. ‘But the location is not as important as its nature. This is not the work of Horus. It cannot be the work of material hands, be they human or xenos.’

‘I suppose we should be grateful for that,’ said Guilliman.

‘We should,’ said the Lion. If the traitor Legions had become capable of such a feat, then the war was over. He looked at the fleet trajectories again and frowned. ‘Some of our smaller vessels are not turning fast enough,’ he said. The port wing of the formation was ragged. It was extending closer to the fortress.

‘Some of ours are struggling too,’ said Sanguinius. ‘Their engines are pushed to their limits.’

‘They should still complete the manoeuvre,’ Guilliman said. ‘But they’ll be very exposed.’

‘Then we must hope…’ Sanguinius began. Then he stopped. The Lion heard his breath catch. When the Angel spoke again, it was with the tone of one caught in the grip of premonition. ‘The structures between the towers…’ he said.

The Lion turned back to the oculus. The angle of the Invincible Reason’s approach had become oblique, though the fortress was so vast, its expanse stretched for an eternity into the void, glowing and pulsing with its unnatural fire. Conical shapes jutted out from the battlements at irregular intervals. They were the size of gas giants. They could not be what they appeared to be.

Sanguinius confirmed the madness. ‘They’re war-horns,’ he said. His tone was flat, and leaden with prophecy.