A crooked real estate manipulator sells worthless land on mortgage to flood refugees, then tries to profit by reselling the land to the state, committing murder in the process, as the Three Mesquiteers work to bring him and his gang to justice.

A phantom-like gunman is murdering the hands at the Circle T Ranch and the Range Busters are recruited by its owner to stop the "phantom". Only, the ranch owner is killed before they can arrive. First film in the Range Buster series.

When Moreland's henchman attack Bob Horner the Range Busters break it up. Horner dies but they get the baby Moreland was after. He must have it to become it's guardian and take control of the Horner ranch. When the henchmen catch up with Alibi, they take the baby cradle not realizing Alibi has substituted his dummy Elmer. Crash having evidence Moreland is the one they want, now has a plan to expose him.

The Cattlemen's Association has called in the Mesquiteers to find cattle rustlers. They get Tex Riley to pose as Stony so Stony can arrive posing as a wanted outlaw. This gets Stony into the gang of rustlers and he alerts Tucson and Lullaby as to the next raid. But Hartley is on hand and unknown to anyone is the rustler's boss and he joins the posse with a plan that will do away with the Mesquiteers.

Talbot uses a phony land grant to rule thirteen million acres, taxing everyone heavily and evicting those who won't pay. The Three Mesquiteers becomes mysterious "night riders" to fight this evil.

Nancy Evans, lovely circus owner, has a ranch that she's never visited, but for sentimental reasons won't sell to Mike Abbott. Her partners, secretly in league with Abbott, sabotage the circus to force Nancy to sell the ranch; instead, she goes there to live. Will her neighbors, the Three Mesquiteers, be a match for the secret swindlers? And what's so valuable about that run-down ranch anyway?

Wells Fargo hires three cowboys to clean up a lawless town.

The notorious outlaw Black Bart has reappeared and the Range Busters are sent to investigate. When they find that Black Bart is now a respectable citizen and that someone is impersonating him, they set a trap for the robber.

Someone wants to kill Magpie Harper. Crash and Dusty arrive too late, Magpie Harper is allready dead.

Cattle are being routinely stolen from a local ranch, and suspicion centers on a local mountain family. But the Three Mesquiteers are wise to the criminals' deeds. But when a ranger is shot and Stony is framed for the crime, it's up to Lullaby and Tucson to prove his innocence.