Following the trajectory of a blood-red comet, the berserk World Eaters blaze a path of destruction across the galaxy in its wake. The small cemetery world of Certus Minor appeals to the Space Marines of the Excoriators Chapter for protection, but the force dispatched to deal with this grim threat is far too small and their losses against the renegades are high. Just as all seems lost, salvation is borne out of legend itself as sinister spectral warriors descend upon this planet of the dead, and the enemies of the Imperium come face to face with those who have already travelled beyond the realm of the living...