Larry Durrant (Laurence Olivier) is a playboy and one of life's losers! Having failed as a farmer in Africa he returns to England and strikes up a relationship with an attractive married model, Wanda (Vivien Leigh). All does not run smooth for the lovers as Wanda's estranged husband appears after a 3 year absence demanding money. A fight breaks out between the two men and during the ensuing scuffle Larry accidently kills the blackmailer in self-defence.
Larry immediately seeks the help of his brother Keith (Leslie Banks), an ambitious and selfish barrister on the brink of becoming a judge. Fearful that any scandal might tarnish his name Keith pleads with his younger brother not to confess to murder. The same evening, Larry meets a destitute former clergyman, John Aloysius Evan (Hay Petrie), near the scene of the murder. Evan steals the victim's wallet and is arrested and charged with murder and held for 21 days until he comes to trial.
Larry and Wanda use the three weeks to get married and enjoy their time together - but the weeks pass quickly. Evan is subsequently found guilty and sentenced to hang and Larry has to decide if he can live with the death of two men on his conscience.