Diabolique

In this heralded French terror classic by director-screenwriter Henri-Georges Clouzot, the wife (Vera Clouzot) of a boys-school headmaster (Paul Merisse) tires of his violent treatment of her, along with his philandering, and teams up with his mistress (Simone Signoret) to drown him and make it appear as a suicide. When the body goes missing and sightings of the supposedly dead man are reported all over town, the two mismatched women must uncover what happened to the body before it's discovered what they've done. Upon its release, Clouzot urged all who saw the film not to reveal its surprise ending---one which still stands as one of the original 'shock' endings.