This movie revolves around the physically and mentally abusive schoolmaster Michel Delasalle (Paul Meurisse). Although he is the master, the school is actually owned by his wife Christina (Vera Clouzot). Michel is openly carrying on an affair with an attractive teacher at the school, Nicole Horner (Simone Signoret). Due to his cruel treatment of the two women, Nicole suggests they conspire together to murder him and make it look like he accidentally drowned. Once the plan has been carried out, Michel’s body vanishes from the swimming pool where the women placed it, and shortly thereafter, strange and ominous events begin occurring around the school.