Martin Roumagnac (Jean Gabin), a humble construction engineer, is building a small villa for himself but those plans get interrupted when he is introduced to Blanche Ferrand (Marlene Dietrich). She has spent many years in Austria, where she found the men dull, and so when she meets the handsome Martin, she is more than passingly interested. After sitting next to each other at a boxing match the two become lovers, and their scenes together indicate that each may have found a lifetime partner. Martin is an old-fashioned man with common taste, whereas Blanche is a bit more refined. As a gesture of his love Martin gives Blanche his finished villa, a selfless act that ruins him financially. All the while, Blanche has also been angling to become the wife of a retired diplomat, Laubry (Marcel Herrand). Determined that if he can't have her no one will, Martin kills Blanche after learning of her infidelity. He is immediately brought to trial and it emerges during the proceedings that she really loved him, leaving Martin riddled with guilt as he awaits to learn his fate.