Sir Wilfred Robarts (Charles Laughton) is a barrister (lawyer) defending Leonard Vole (Tyrone Power), accused of murdering a wealthy older woman who'd recently made him her main beneficiary, causing the appearance of an affair between them that ended when he killed her for her money. Sir Wilfrid takes the case after talking to Vole's wife Christine (Marlene Dietrich), who stands to provide her husband with a solid alibi. But the story has at least two more twists when, first, Christine testifies for the prosecution against her husband, that he confessed to her that he did the murder. She does so after revealing that she was, in fact, married to someone else, and therefore not Vole's wife. But then, second, another woman comes forth, who seems to exonerate Vole after all, by way of letters she possesses, that were written by Christine that contradict her testimony. At this point the audience inevitably wonders what other twists might be in store.