On board a train bound for the port city of Le Havre, France, railroad stationmaster Roubard murders Grandmorin, who seduced his beautiful young wife, Severine. Engineer Jacques Lantier, stuck in Le Havre while the train is being repaired, also begins a passionate affair with Severine, who tries to entice the handsome stranger to murder her controlling husband. However, Lantier has a secret urge of his own that changes everything.