 In Kansas City, the deranged middle-age Donna Germaine (Barbara Niven) stabs and kills her lover, when he calls off their relationship to stay with his wife. Donna uses an excuse to move to the house of her aunt, and she becomes obsessed in their neighbor, the executive William Costigan (Perry King). The sick Donna plots an evil scheme to take William from his wife Jeannie Costigan (Susan Bakely).