A rather cruel doctor (Paul Muller) discovers that his wife (Barbara Steele) is having it away with another man so he tortures them both to death, then uses their ashes as compost for a plant. Once he discovers that his wife has left her considerable fortune to her deranged sister (again, Barbara Steele). he marries her with a view to having her certified and thus gaining the money for himself. Well, as you'd expect, his cunning plan doesn't quite go as he would have liked. Once the psychiatrist "Dr. Joyce" (Laurence Clift) arrives at his castle, the ghosts of his victims appear and all hell b...