Fritz Lang directed this modernized adaptation of Emile Zola’s novel, The Human Beast. A Korean War veteran returns to being a railroad engineer and falls in love with the pretty wife of a hot-tempered and jealous railroad employee who is fired.
Engineer Jeff Warren (Glenn Ford) drives a train with Alec Simmons (Edgar Buchanan) after returning from three years in Korea. Carl Buckley (Broderick Crawford) has been promoted and is married. Jeff is staying with Alec, his wife Ellen, and their daughter Vera (Diane DeLaire), who is now grown. Jeff gives Vera a Japanese robe.
Carl comes home to his wife Vicki Buckley (Gloria Grahame) and says he blew up at the boss and got fired. Vicki says they can go east or she can work. Carl asks her to put in a good word for him with John Owens, and she reluctantly agrees to call him.
Carl and Vicki are on Jeff’s train, and she goes to see John Owens. Vicki’s sister gets dressed and goes out. Vicki comes in and tells Carl he got his job back. He asks her where she was for five hours. She says they went out for a drink. Carl is suspicious and jealous. He slaps her and threatens to kill her unless she admits it. He makes her write a letter to John Owens. It suggests a meeting on the train. Jeff gets free passage. On the train Carl takes Vicki to John’s compartment and pushes his way in. After killing him, Carl wipes the blood off his pocket knife and takes money out of John’s wallet. They see Jeff and go the other way. Carl tells Vicki to get Jeff out of the way. Jeff joins her for a drink, and he takes her to a room for a smoke. He kisses her, and she leaves. Carl and Vicki get off the train, and they see Jeff.
Carl burns his bloody clothes but not her letter, keeping it to blackmail her. Jeff joins Vera, Ellen, and Alec at the breakfast table. Alec says Owens was murdered on the train.
At a court hearing the brakeman says Jeff Warren was there. Jeff is questioned but does not name anyone going into that compartment.
In a bar Carl buys Jeff a drink. A man asks Vicki to dance, and Carl gets angry. Jeff helps drunk Carl get home. Carl goes to bed, and Jeff asks Vicki for an explanation. He says he saw her come out of the car where Owens was killed. She says she found Owens dead. She says Carl is terribly jealous and shows Jeff her bruises.
Jeff drives a train. Carl comes home to Vicki and takes a drink. She does not let him touch her. Carl says he loves her, and she asks him to destroy the letter. She sees where he hides money. He leaves, and she finds the box; but it only contains money. She calls Jeff. At the railroad tracks Vicki tells Jeff about how she got involved with Carl. She says she can’t stand to have Carl touch her. He says people make mistakes. She asks if it is difficult for a soldier to kill a man. He is about to kiss her, and they hide from a night watchman. They plan to meet in the city, and he kisses her.
At the train Vera sells dance tickets to Jeff. Vera says Mrs. Buckley is very pretty and asks if he is in love with her. Vera cries, and sees Vicki get on the train. Alec asks Jeff why he was out late and warns him to stay away from a married woman.
In an apartment Jeff asks Vicki to leave Carl, but she says she can’t. She says she is afraid of the police. She says Carl killed Owens, and she saw it. She says Carl made her write a letter to Owens. Jeff says he has to go to the police, or he will be guilty too. She says Carl beat her because of Owens. Jeff says he won’t go and kisses her.
Jeff gets off the engine and sees Carl walk by. Vera comes in to Jeff’s room and says Mrs. Buckley is on the phone, but he tells her he will call back later. Vera asks Jeff what he wants. She says he needs the right girl, but he asks how to tell the right girl from the wrong one. She says there are other kinds of love. She leaves his room.
Jeff goes to Vicki, who says that Carl was fired and sold the house. They are leaving tomorrow. Jeff says he won’t let her. Jeff offers to get the letter. She is afraid Carl will kill her if finds out about them. Vicki says it is too late. She hopes something will happen to Carl.
Carl is very drunk and staggers on the street. Jeff follows him to the railroad yard. Jeff grabs a wrench. Jeff goes back to Vicki and says he didn’t do it. He tells her the whole thing is wrong and dirty. He says killing in a war is different. He says she never loved him. She confesses that Owens seduced her when she was sixteen. Jeff says it is finished. She admits it was wrong to ask him to kill Carl. She says she loves him. He leaves the letter for her and goes out.
Vicki is riding on Jeff’s train, and Carl comes into her compartment. He asks her not to leave him. He suspects it is Warren, but she says she is going away alone. She says Jeff left her because she asked him to kill Carl. He tries to choke her, and she struggles and then falls. Jeff drives the train and pulls the whistle.
This film noir portrays characters trapped by their passions. As Vicki’s sister put it, it is better for a woman to be good-looking than smart because most men are more influenced by their eyes than by their brains. Humans acting without reason may be no better than beasts.