A squad of alien hunters from the elite and secretive Deathwatch descend upon the Teramus system, intent upon the destruction of alien pirates who have been ravaging the area, preying upon citizens of the Imperium. As they stalk their quarry through the system’s asteroid fields, Sergeant Courlanth and his kill-team discover that there are secrets and lies at work in Teramus, and that their mission may be more complicated than they know.