Ex-soldier Frank Brayker is the guardian of an ancient key that can unlock tremendous evil; the sinister Collector is a demon who wants the key so he can initiate the apocalypse. On the run from wicked mercenaries for almost 90 years, Brayker finally stops in at a boarding house in New Mexico where — with the help of its residents — he plans to face off against the Collector and his band of ghouls, preventing them from ever seizing the key. High-level demons collect low-level demons as warriors in attempt to obtain a key containing the blood of Christ. The key is guarded by immortal warriors called Demon Knights.