Discover what happens when a Broken One is freed, and a daemonic conspiracy threatens to unveil the dark rituals of the Exorcists. The Exorcists are a Space Marine Chapter unlike any other. To combat the forces of Chaos, they willingly accept daemonic possession, knowing that once it is purged their shattered souls will no longer be susceptible to corruption. Those who fail the banishment trials become Broken Ones, living prisons for the terrors expelled from their brethren. Should such desperate measures become known to the wider Imperium, there is little doubt the Chapter would stand accused of the vilest of heresies. When a daemonic conspiracy sees a Broken One freed, the Exorcists dispatch their Vanguard elite, the Hexbreakers, in a desperate quest to hunt it down. But the connection between their quarry and the commander of the strike force, Daggan Zaidu, is more than it first appears, and the Hexbreakers find themselves in a race against time to find the Broken One before their secrets are revealed to the Imperium, bringing damnation to the entire Chapter.