In this WW II film meant to discourage the purchase of black market beef, the Range Busters are called on to fight cattle rustlers. This time they're up against a gang that strikes fast by hauling the beef away in trucks.
Rodeo contestants Johnny King and Corrigan meet, their fathers having been members of the Range Busters. When Johnny is knocked unconscious, time reverts to their father's era and the Range Busters are soon involved in the scheme to get Railroad right-of-way across Mother Slocum's ranch. When she is tricked into signing a release, the Range Busters find their job more difficult as the Sheriff is in with the crooks.
The Range Busters investigate sabotage at a mining community and uncover a gang of Nazi spies.
The Range Busters head for Pinto Basin where a series of stage robberies have occurred. To try and find the gang's boss, Crash sends out a empty money box. The plan backfires when the boss has the Range Busters identified as the robbers. Thinking it is now safe, the bank sends out a big money shipment. Needing to rob the stage, the boss gets the boys out of jail so they can be blamed. But this is just the chance they need to catch the robbers.
Someone wants to kill Magpie Harper. Crash and Dusty arrive too late, Magpie Harper is allready dead.
In the midst of some friendly horseplay on their "Flying R" ranch, the Range Busters, Crash Corrigan, Dusty King and Alibi Terhune, are sobered by the arrival of a buckboard bearing their old friend Larry Meadows and his niece Dorrie Willard. Meadows seeks their aid against a gang of outlaws terrorizing his town. Ernie Willard, Dorrie's brother, has been taken in by Tex Laughlin who is using the Willard ranch as an undercover for his real occupation as a member of a gang of outlaws led by Tim Douglas, a supposed friend of the Willards.
Bolton's men blow up the wagon carrying the mine payroll and Marshal Crash Corrigan is supposedly killed in the explosion. A man finds his badge and gives it to Bolton. Thinking Crash dead, Bolton gives the badge away and it ends up with the Sheriff. Crash is OK and the Range Busters know Bolton is the head of the gang but that he gets his orders from someone else and that is the man they want.
Hammond is after the Craig ranch and has framed Charlie Craig for murder. Mother Craig brings in the Range Busters. They capture one of Hammond's men and Alibi plans to trick him into a confession as to who the real murderer is. Meanwhile, Denny has overheard Hammond's plans for his next move and he and Crash set out to round up the gang.
When a gang of outlaws led by Faro Wilson starts swiping payrolls and terrorizing the residents of a small Western town, courageous Range Busters Crash, Denny and Alibi gallop onto the scene to set things straight.