The Narrow Margin is a 1952 American film noir starring Charles McGraw and Marie Windsor. Directed by Richard Fleischer, the RKO picture was written by Earl Felton, based on an unpublished story written by Martin Goldsmith and Jack Leonard. The screenplay by Earl Felton was nominated for an Academy Award. A police detective plays a deadly game of cat-and-mouse aboard a train with mob assassins out to stop a slain gangster's widow before she can testify before a grand jury. Plot Detective Sergeant Walter Brown (Charles McGraw) of the Los Angeles Police Department and his partner are assigned to protect a mob boss's widow, Mrs. Frankie Neall (Marie Windsor), as she rides a train from Chicago to Los Angeles to testify before a grand jury. She is also carrying a payoff list that belonged to her murdered husband. The mob's hitmen do not know what she looks like. On the way to pick her up, Brown bets his partner and friend, Sergeant Gus Forbes (Don Beddoe), what she will be like: "She's the sixty-cent special. Cheap. Flashy. Strictly poison under the gravy." As the detectives and Mrs. Neall leave her apartment, they are waylaid by a mob assassin named Densel (Peter Virgo). Forbes is shot to death, but Densel, although wounded by Brown, escapes. At the train station, Brown discovers that he has been followed by gangster Joseph Kemp (David Clarke). Kemp identifies Brown as the detective even before they board the train. Each man knows the other is a mortal enemy. With the help of a conductor, Kemp comes into Brown's room while Brown is there, under the pretense that he is looking for lost luggage. Meanwhile, an overweight man confronts Brown in front of other passengers as to why Brown is holding a two room compartment, while he is in the upper berth of a section. Kemp tries to open the door to the next compartment, where Mrs. Neall is hiding, but Brown tells the conductor that the room is empty, and Kemp and the conductor leave. Brown knows that Kemp will come back to Mrs. Neall's room, so he hides Mrs. Neall in the ladies room with all of her luggage, and goes to the dining car so Kemp will know that the room is unguarded. Kemp then goes back and searches both rooms, finding nothing. After Kemp returns to the dining car, Brown leaves the dining