U.S. Marshal Steve Lawlor (Charles Starrett) comes to the aid of cattle-rancher Madge Conway (Iris Meredith) after her father (Edward LeSaint) is murdered by a gang of cattle rustlers, and she tries to carry on with the help of her ranch-foreman, Bob (Bob Nolan), and her loyal ranch hands (Sons of the Pioneers). Aided by his friend and fellow lawman, U.S. Marshal McLain (LeRoy Mason), Lawlor, posing as an outlaw, suspects Matt Taylor (Dick Curtis) and banker Frank Parker (Robert Fiske) of being behind the rustling and killing.