When forge world Tophet VI is attacked by the Iron Warriors, the Imperium responds in force, sending a mixed force of Subjugators Space Marines and the engines of the Legio Debellator to defend it assets. Though the Traitor Marines present a terrible enemy in and of themselves, the Warlord-class Battle Titan that heads up their attacks is an even worse threat, having the power to carry the battle for its dark masters. But why does this enemy god machine bear the mark of the Legio Debellator, and just how far will the legio go to destroy their fallen engine and avenge their dishonour? Read it because Action, intrigue, historical secrets and, oh yeah, skyscraper-sized killing machines abound in this brand new story.