The film's opening intertitle reads:
- "This story is told against a background of political unrest in a city of Northern Ireland. It is not concerned with the struggle between the law and an illegal organisation, but only with the conflict in the hearts of the people when they become unexpectedly involved."
The city and the illegal organisation are never explicitly named in the film, but the protagonist is a chieftan in an IRA-like organization. James Mason plays Johnny McQueen, who is trying to escape from the police after an ill-advised bank robbery meant to replenish the organization's coffers. The film follows McQueen, who has been wounded in the robbery, through an increasingly surreal odyssey over a day and a night. The bleak city, with its labyrinth of havens and traps, draws Johnny ever deeper into itself as the night wears on.
Carol Reed / Robert Krasker / James Mason = A Golden Teamng