Henri Cassin, a distinguished Parisian detective takes his first vacation in eleven years and journeys to the seemingly idyllic Michaud family inn in St. Margot. There he finds himself drawn to lovely young Nanette Michaud. Though Nanette… More Henri Cassin, a distinguished Parisian detective takes his first vacation in eleven years and journeys to the seemingly idyllic Michaud family inn in St. Margot. There he finds himself drawn to lovely young Nanette Michaud. Though Nanette is already engaged to local farmer Leon Archard, her mother wants her to marry Henri the detective in hopes of improving Nanette's social status. Soon a May-December romance blooms and Madame Michaud's fondest dreams come true. Unfortunately, her husband is against the match. Leon vows he will never stop pursuing Nanette and storms off. Later she vanishes and Henri finds her strangled corpse floating in a local river. He is deeply distraught and vows to bring the criminal to justice. Leon is the prime suspect, but then he too is found dead. The only clue Henri has is a muddy footprint and later a note announcing another murder. Madame Michaud is the next to die. After that, Henri returns to Paris to talk with his superior. Together they devise a physical description based on the footprint and take it to police artist. As a drawing takes shape a terrible notion dawns on Henri, one that is soon corroborated. So Dark the Night was the second film noir of Joseph H. Lewis. It is one of the few that is set in Europe and utilized special lighting and camera techniques designed to give viewers a detective-eye view of the crime and its ultimately grim solution.