So Dark the Night plot
"Most Baffling of Mysteries!"
France, 1940s. Henri Cassin is a middle-aged police inspector from Paris, who is taking a vacation after many years. Henri takes up residence in the inn of the Michaud family, in the rural village of St. Margaux. There he falls in love with Nanette, the innkeeper's young daughter. However, Nanette is already engaged to local farmer Leon Archard. Unlike her husband Pierre, Nanette's ambitious mother sees a marriage between her daughter and Henri and sees benefits for herself, especially for her social status. Nanette marries Henri, but Leon indicates that he will not leave Nanette alone. One day Nanette is found murdered and Leon is immediately the prime suspect.