Spain 1640, the reverend superior nun Mariana, attends the death of her younger sister, Isabel's husband, who is overcome with hopelessness and heartache. Isabel then kisses and caresses the cadaver's exposed body as if he were still alive. Mother Mariana
16-year-old Maria is forced into Serra D'Aires convent, secretly run by Satanists. Her confessor is in collusion with the Mother Superior. Maria is tortured, forced into sex with men, women, and the horned Devil, and told that it's all a bad dream. She writes a letter to God, and a Knight rescues her, only to fall into the hands of the Inquisition, put on the rack, and condemned to death like Joan of Arc.