Le Havre, France, in 1949. In a town that still shows the scars of war, several friends meet up in Albert's café. One of them, Laurent, has lost his job on the docks and his marriage to Madeleine is falling apart. He knows that his wife wants to start an affair with friend, Jean Sauviot. Jean is a lonely man who is attracted to Madeleine but doesn't want to commit himself to the wife of a friend. On the day that Madeleine tells her husband that she is seeing Jean, Laurent goes looking for Jean to find an explanation. Arriving on the docks in the evening, he attacks an American sailor who looks like Jean, but the man fights back and runs away after killing Laurent accidentally. Madeleine thinks that Laurent was killed by Jean and believes that she can start a new life with her lover. The police have other ideas...