The Narrow Margin

Detective Sergeant Walter Brown (Charles McGraw) is assigned to protect a key witness, Mrs. Frankie Neall (Marie Windsor), on a cross-country train journey from Chicago to Los Angeles as she testifies against a mob boss and carries an important payoff list. With the help of a conductor, Joseph Kemp (Gordon Gebert), Brown must navigate a complex web of threats and danger while trying to keep Mrs. Neall safe from a ruthless hitman, Densel. As they journey through the night, Brown befriends passenger Ann Sinclair (Jacqueline White) and her young son Tommy, but soon discovers that she is actually an undercover policewoman posing as Mrs. Neall.