Synopsis

At a strict boarding school, the frail wife of its cruel headmaster and his resolute mistress form an uneasy alliance to eliminate him. Their carefully arranged murder appears successful, but the man's body soon vanishes. As unsettling signs begin to surface around the school, the women find themselves trapped in a tightening web of fear, suspicion, and psychological torment.

Factoids & Trivia

• The film adapts the 1952 mystery novel *Celle qui n'etait plus* by Pierre Boileau and Thomas Narcejac.

• The screen rights became the subject of a famous race: the filmmaker secured them shortly before Alfred Hitchcock could do so. Hitchcock's later interest in the material helped cement the film's connection to his suspense tradition.

• The production originally faced a title problem because "Les Diaboliques" was associated with an earlier literary work. The title was eventually cleared for use.

• Its American release was promoted with a strong anti-spoiler campaign, asking audiences not to reveal the ending to prospective viewers.

• Some American theaters used a no-late-seating policy, requiring patrons to arrive before the feature began. The policy was later associated more famously with Alfred Hitchcock's *Psycho*.

• The film became an important influence on later psychological thrillers and is frequently discussed alongside *Psycho* as a key work in the development of modern suspense horror.

• The film was a major international success and remains one of the most highly regarded French thrillers of the 1950s.