A girl is murdered and the story goes into the exploration of the three most likely suspects.

During a day of shopping at Manhattan's mod boutiques, Karen, an impressionable young woman, tells her socialite friend Tracy about a filmmaker, Christopher, with whom she has fallen in love. While Tracy is at her bank, Karen catches sight of Christopher and follows him to his studio. There she finds him screening the rushes of a sex film which he admits is his own. Angry and humiliated at having been discovered, Christopher confesses that he is being forced to do the film in order to make enough money to divorce his wife. When Karen pleads with him to allow her to raise the money, he refuses and storms out. Returning to Tracy's car, Karen finds an envelope full of jewels and a fortune in bonds and cash. Thrilled at her good luck, she races back to Christopher's studio, where she is stabbed with a trick icepick and squirted with catsup by Otto, the prankster star of Christopher's film. After cleaning herself up, Karen decides to remain in the studio and wait for Christopher. Suddenly, the blinding lights go on, and she is brutally murdered, this time in earnest, with an icepick. The three principal suspects then relate their individual versions of the events surrounding the slaying: Tracy sees Otto carry a trunk, apparently containing Karen's body, to a cemetery; Otto tries to lure the murderer to a cemetery by means of an empty trunk from which a blood-stained dress is protruding; and Christopher, who seems to have been following the two women, is an eyewitness to the murder. Once the three conflicting stories have been told, it is revealed that Christopher is the real killer.