The story of Georges Clouzot's Diabolique unfolds in a French provincial town where Michel Delassalle, a sadistic headmaster of a school belonging to his wife Christina, a fragile young woman with a weak heart, carries on an affair with Nicole Horner, a strong, forceful teacher who has been his mistress from the day she arrived. He has, however, treated her as badly as his wife, and the two women have been driven into an alliance against him. Together they work out an elaborate plot to rid themselves of their common tormentor. Luring him away from the school to Nicole's cheap lodging house, they induce him to drink some doctored whiskey, and drown him in a bath. The body is later wrapped in a nylon tablecloth, placed into a laundry basket, and during the night, is transported back to the school, and thrown into the grimy waters of the school swimming pool. When, shortly after, the pool is drained, the women are shocked to discover that no corpse is found, and soon enough strange and mysterious occurrences begin to happen, along with the subsequent reported sightings of the dead headmaster.
Director Henri-Georges Clouzot has always been labeled as the 'French Hitchcock' and Diabolique has always been quoted as "the greatest Hitchcock film that Hitchcock did not make." Diabolique is a near-perfect movie about a near-perfect murder, a film in which the director's methods are equally matched as the killers, in cunning and ruthlessness. Clouzot and his style of filmmaking have been considered some of the most thrilling and scariest films of the French cinema, as legendary critic Andre Bazin stated that Diabolique was Clouzot's "most perfect" film. I believe that the infamous bathtub sequence in the climax of the film is as shocking or even more so then Psycho's infamous shower scene, and ironically Robert Bloch, the author of the novel Psycho, has stated in an interview that his all-time favorite horror film is Les Diabolique. Hitchcock was said to also be a huge admirer of Clouzot's film and even screened it for the writers of Vertigo, because the murder plot and the using and manipulation of an innocent victim were similar themes used in both stories.