In Mars’ orbit, the Fourth Sphere fleet reformed. It was the largest of the four defence fleets in the Solar System. Monitor craft from the Solar Auxilia and the Jovian Void Clans bulked its numbers, and with them were the great orbital assault and bombardment craft of the Imperial Fists. The gun-studded bulk of the Blade of Inwit lay beside the Blade Absolute, Fist of Judgement, Truth’s Warden and Tyrant Bane. Sub-fleets of gunboats, destroyers and lance cruisers orbited the largest vessels. For years they had fought and held the enemy to the surface of the Red Planet; now they broke that cordon.

On the battle-barge Fortress of Eternity, Lord Castellan Camba Diaz waited. He had recalled all his forces from the surface of Mars. Raiding expeditions had been pulled back. Reconnaissance companies had shed their wargear and taken up the weapons of void war. Lexmechanics and magos-ordinators zeroed in guns. Minelayers swept the volumes of space that the enemy would have to move through. Faint and broken signals reached out to the Falcon fleets of the White Scars that were tracking the enemy as they closed on the planet.

Camba Diaz listened to the scratched, crackling words alone in his arming chamber. Other than the sounds of the signals, he waited in silence. That was his way, the way of the planet that bore him, the people that had raised him and the Legion that had been his life. Inwit, by turns burning and dark, had been a remorseless teacher and cold parent to men of stone who bore the burdens and pains that others would not. He thought of all those who could have faced this moment. Pollux, thought dead at Phall, now half a galaxy away; Sigismund, sent to watch the edge of night with a sword in his hand; Halbract; Rann – all of them brothers, all of them warriors that another age would have made masters of war.

Rogal Dorn had told him why the Fourth Sphere command was his, though.

‘Temperament,’ the Praetorian had said, and Camba Diaz had thought that he had understood his lord’s meaning. In the years of conflict around and on the Red Planet – sapping endless war, thousands of cuts drawing blood bit by bit – he had felt his stillness and patience become the foundation of his command. His temperament allowed him to bear those trials and rise to conflict each day afresh. He had thought that was what Dorn had meant. He thought he had understood his lord. He had not.

Temperament… the stone-soul of Inwit, and the will to look up at the stars falling from the sky and not blink. This was a moment that tested temperament, the moment when the heavens were falling.

The lights of the descending fleet grew. Auspex readings and reports from the Falcon fleets began to build a picture of what each growing mote of light was, of what was coming for them – seven thousand ships counted at an estimate…