The Arks of Omen have sown terror and death from one side of the galaxy to the other. Despite the efforts of those who opposed them, their masters have gathered enough arcane artefacts for Vashtorr the Arkifane to fashion his monstrous Key. The hour draws nigh when the daemon and the Despoiler will between them awaken this engine of terrible power.

At the end of a long and bloody road, the armies of the Farsight Enclaves stand poised to secure final victory over the Ork hordes. As Commander Farsight's audacious attack reaches a critical stage, an Ark of Omen and its attendant Balefleet erupt from the warp to shatter the balance of the conflict.

As the massive space hulks known as the Arks of Omen spread the flames of Abaddon’s war across the galaxy, a powerful agent of the Inquisition ignites an ancient archeotech beacon – praying that its light might drive back the darkness. Yet that which burns bright may be seen from afar. Deep in the void, the hateful gaze of Angron, Daemon Primarch of the World Eaters, is drawn towards the light. Driven by his fury, the Red Angel vows to drown the beacon in blood.

The Great Rift has torn the Emperor's realm in two. Ancient alien empires rise from the ashes of prehistory to claw at the dying stars. Predatory nightmares boil from the outer darkness, while everywhere the veil of reality wears thin and the flames of war rise ever higher. Day by day, battle upon battle, the galaxy careens ever closer to total annihiliation.