Corrupt businessman Steiger flees Scotland Yard to Mexico. On the way there he kills an acquaintance on the train and steals his identity. He quickly finds the man he killed was running from his own troubles, as well as the fact that the dead man isn't dead. . .

Well done morality tale disguised as a crime story, one of the best film adaptations of Greene, told with efficiency (and an excellent performance by Dolores as the dog/embodiment of guilty conscience). Some of the acting is variable, and the American ambience not always convincing, but still pretty close to what one would call "a lost classic." That does depend on how high a tolerance you have for Steiger's at times very hammy method acting, of course. James Bernard's score does sort of convince one that Steiger is going to turn into a monster at certain points, though.