In the grim nightmare future of the 41st millennium, the witch-hunting zealots of the the Sisters of Battle stand between humanity and damnation. From the elite Seraphim warriors to the berserk Sisters Repentia, they are the strong arm of the Ecclesiarchy and the brutal hammer of witches.

When dangerous psychic heretic Torris Vaun escapes from her custody, Seraphim Miriya is disgraced in the eyes of her fellow sisters and superiors. Following Vaun's trail to the planet Neva, Miriya takes her sisters in pursuit and, along with Hospitalier Sister Verity, starts her investigations.

When they uncover a terrifying plot that could threaten the future of the Imperium, is Miriya's and Verity's faith strong enough for them to triumph?