In 16th century France, Inquisitor and magistrate Bernard de Fossey (Paul Naschy) travels to the plague-ridden region of Peyriac in search of witches and devil worshippers. Local beauty Catherine (Daniela Giordano) quickly catches his eye, tormenting his with impure thoughts, although her affections lie with her handsome fiance Jean. Meanwhile, embittered one-eyed manservant Renover (Antonio Iranzo) presents Bernard with his first group of torture victims when he accuses several sexy young things who spurned his advances of being wtiches responsible for the plague. One by one beautiful women are tortured victims when he accuses several sexy young things who spurned his advances of being witches responsible for the plague. One by one beautiful women are tortured on the rack then burned at the stake. No-one seems able to halt the Inquisition's reign of terror or the baseless accusations that cause so many innocent deaths. Whe Jean dies in mysterious circumstances, Catherine allies herself with Satan to get revenge on her enemis - foremost among them, de Fossey himself.