An updating of Zola's orphan girl story finds Therese married to her elderly, sickly cousin, Camille Raquin. His dominating mother lives with them. It is a dull and empty life, void of romance. One day, Camille, i his capacity as a freight controller, befriends the truck driver Laurent, who after an initial conflict, gets him drunk (evidently for the first time in his life) and brings him, half-conscious, home. For Laurent and Therese, it is love at first sight. Laurent accepts Camille's invitation to dinner, where he witnesses first-hand the disdainful treatment of Therese. Laurent and Therese meet clandestinely a few times, and Laurent repeatedly pleads with Therese to come away with him. Suspicious, Camille takes his wife by express train to Paris. Laurent hears about the planned trip from Therese shortly before their departure and shows up on the same train, to the surprise of Camille. She leaves the compartment to talk to him, but Camille follows and surprises them together. Camille and Laurent fight, and Laurent throws Camille from the train. Laurent and Therese agree to keep silent. The police take Therese into custody when she reports her husband missing, and show her his body. They grill her for hours, but she does not break down. Camille's mother becomes catatonic, and Therese continues to look after her. Finally, a man who was on the train has put two and two together and looks up Therese in her (mother-in-law's) shop). He is a war veteran and needs money to start his own business. He demands 500,000 francs for his silence. Therese meets with Laurent, who senses that something is wrong, she explains the situation and they meet with the blackmailer together. Laurent loses his temper and strikes the blackmailer several times, but the blackmailer keeps his cool. He warns Laurent that he has enough combat experience to defend himself, and tells them to think it over. Meanwhile, he writes a letter to the authorities explaining his view of the murder and gives it to a neighbor girl with instructions to mail it if he doesn't return by 5 PM. He meets with the lovers again, arriving late because of trouble with his motorcycle. They can only come up with 400,00 francs, but he is satisfied that. In return, Laurent and Therese ask him to write and sign an incriminating statement as insurance against further blackmail. The y watch anxiously as he leaves. Once again he has trouble starting his motorcycle. While he is working on it a truck swerves to avoid a little girl crossing the street and runs into the motorcycle, driving it and the blackmailer through the entrance of a nearby building and pinning him under his motorcycle. A crowd gathers around and Laurent pushes through it to pull the blackmailer out of the rubble. The blackmailer is still alive and Laurent carries him into the haberdashery and instructs Therese to call for a doctor. The blackmailer comes to and tries to tell Laurent about the letter but cannot make himself intelligible. Laurent tries to shake it out of him, but he dies on the spot. The film closes with a shot of the neighbor girl giving the letter to the postman.