Police captain Valence, an insomniac since the death of his wife in a car accident. heads a night squad which covers a Right Bank sector of Paris. Methodical and rigorous, he takes personal risks in order to avoid violence. When a well-known lawyer is found murdered in a hotel room, Valence investigates. In the early hours of the morning, he hunts the truth into the darkest reaches of urban delinquency and organized crime.