A cheating wife of a demented evil scientist (not a person to cross!) has an affair. The husband kills his wife and her lover. To retain the estate, he marries his wife's half-wacky sister and tries to scare her to death. The ghosts of the murder victims also join the party. Talk about a dysfunctional family.
Barbara Steele, in a dual role, plays the wife and step-sister (with blonde hair!).