 After being threatened by witchcraft in Africa, Gwen Mayfield (Joan Fontaine) has a nervous breakdown and returns to England. She is invited to teach in a private school, owned by the wealthy Alan Bax (Alec McCowen) and his sister Stephanie Bax (Kay Walsh), in the village of Heddaby. After a period in the place, she witnesses weird events with locals, and she realizes that the place is indeed a coven and her student Linda Rigg (Ingrid Brett) is being prepared for a sacrifice.