1970s Italian horror directed by Sergio Martino. After losing her unborn child in a car accident, Jane (Edwige Fenech) slowly begins to lose her grip on reality and becomes convinced she's being stalked by a knife-wielding killer. Her sister Barbara (Susan Scott) suggests she seek professional help but when that fails Jane's neighbour introduces her to a satanic cult that practices black magic and proposes that its Black Mass ritual can cure her ills. Will it be successful or will it only deepen her despair and push her further towards insanity?