The story blends elements of thriller and horror , with the plot focusing on a woman and her husband's mistress who conspire to murder the man. It was the 10th highest-grossing film of the year in France, with a total of 3,, admissions. Clouzot, after finishing The Wages of Fear , optioned the screenplay rights, preventing Alfred Hitchcock from making the film. A second-rate boarding school in Saint-Cloud , Hauts-de-Seine , in the Paris metropolitan area , [ 6 ] is run by the tyrannical and cruel Michel Delassalle.
Michel also has an extramarital relationship with Nicole Horner, another teacher at the school. Rather than antagonism, the two women have a somewhat close relationship, primarily based on their apparent mutual hatred of Michel. He is cruel to the students, beats Nicole, and mocks Christina about her heart condition. Unable to stand his mistreatment any longer, Nicole devises a plan to get rid of Michel forever.
Though hesitant at first, Christina ultimately consents to help Nicole. Using a threatened divorce to lure Michel to Nicole's apartment building in Niort , a town several hundred kilometers away, Christina sedates him.
The two women then drown him in a bathtub and, driving back to the school, dump his body in the neglected swimming pool. When his corpse floats to the top, they think it will appear to have been an accident. Almost everything goes according to their plans until the body fails to surface. Michel's corpse is nowhere to be found when the pool is drained.
Afterwards, the suit that Michel had been wearing when they drowned him is returned from the dry cleaners. When the proprietor of the dry cleaners also returns a key to a room in a nearby hotel that was with the clothes, Christina goes to the room. There, the cleaning man tells her that Michel had kept the room for a while but was rarely if ever seen and stored nothing there.
