US marshals Ken, Hoot and Bob stop a gang dressed as Indians from robbing the stage. After getting repairs at the relay station, but before they get to town, another trap is set, but they get away. In town, they search the stage and find nothing. But hidden in the axle grease can are diamonds. Polini wants them cut into smaller diamonds so that he can easily dispose of them. Throughout this Western, the courageous trio faces off against cunning opponents, including the gang's merciless leader (Ian Keith) and an unsuspecting banker (Karl Hackett).
Ken Maynard
as Ken Maynard
Hoot Gibson
as Hoot Gibson
Bob Steele
as Bob Steele
Myrna Dell
as Ruth Hampton
Ian Keith
as Polini
Ernie Adams
as Warren, the Jewel Cutter
Karl Hackett
as Banker Steve Lynch
Charles King
as Henchman Duke Rollins
Dan White
as Engineer Jim Lockwood
George Chesebro
as Henchman Ace
Charles Murray Jr.
as Ted Hodges (as Chas. Murray Jr.)
John Bridges
as Henchman
