In this entry in the long-running series of westerns, the Three Mesquiteers transform their ranch into a prison farm to provide a model for prison reform. They are opposed by a local contractor who wants to build a standard prison.
Death stalked Garou's Landing, in the Canadian frozen north, but who was the killer who murdered two men and left them huddled in the snow. Sergeant Renfrew (James Newill, of the Royal Canadian Mounted Police, accompanied by his dog, Silver King (Silver King the Dog), and Kay Larkin (Terry Walker) the daughter of the man, Andrew Larkin (Robert Frazer) accused of the crime, sets out to solve the crime and bring the real killer to justice.
Heading up the Chisholm Trail with a small herd and just a few men, Breezy has his cattle rustled by Curley and his gang. Returning to Texas, Breezy convinces the ranchers to send their cattle north in one big herd guarded by a lot of men. Outnumbered, Curley has a plan to get the cattle.
It's cattlemen versus sheepmen and Trigger Gargan appears to be the leader of the gang causing the trouble. But unknown to Ranger Tex Lawrence, the respected town citizen Barrow is the boss and is tipping off the gang as to the Ranger's activities.
Caldwell and Nixon have their men rob the stage and then critcize the Sheriff for not catching the robbers. With her father the Sheriff under pressure, Mary sends for Hoppy who finds the stolen money and sets a trap to bring in the entire gang.
Tom Grant has found a rich gold vein and Bart Eaton is after it. Tom's sister Mary heads for the gold fields and Eaton and his men follow. Eaton teams up with Ace Daggett who plans to doublecross him and get the gold for himself. They frame Tom for murder and then try to get him to sign over his claim. The famous scout Tex Houston is on hand, escaping the attempts on his life, saving Mary from various perils, and trying to bring in the real killer and clear Tom.
Brad Buckner has just bought a ranch. Murdock keeps his rustled cattle on the ranch and sends his men to kill Buckner just as they did the previous owners. But Buckner and his men foil their attempts and decide to search the ranch. To throw Buckner off he kidnaps Buckner's girlfriend and the Sheriff and makes plans to drive the cattle across the border.
A group of "Phantom Raiders" interfere with a cattle drive from Texas to Abilene; fortunately, U.S. Marshal Wild Bill Hickok is appointed to ensure the success of the mission.
Hoppy's friend Dennis owns a rich gold mine. Frazier who owns the adjoining mine and wants the Dennis mine, has Dennis killed. Hoppy steps in to take over running the Dennis mine and learns Frazier's men sneak into and work the Dennis mine at night. Hoppy captures one of Frazier's men only to be captured in return by Frazier and left to die in a burning building.
Bradley and sidekick Sharpe are sent west to investigate the murders of pony express riders who are being killed to prevent the Spanish Land Grant papers going to Washington for registration.
Riders of the Black Hills is a 1938 American Western directed by George Sherman. The intrepid cowboys known as the Three Mesquiteers; Stony (Robert Livingston), Tucson (Ray Corrigan) and Lullaby (Max Terhune) are on the case when rancher Peg Garth's (Maude Eburne) prize racehorse is abducted by bookie Rod Stevens (Tom London) and a secret cohort to prevent it from winning an important race.
When a fellow ranger (Julian Madison) is brutally murdered, the Captain sends Dave Austin to investigate the crime, only to stumble upon a money-laundering scheme in the works. With one eye on the killer (Ted Adams), Austin tries to unravel the racket. But keeping his true identity under wraps could be a problem. Rex Lease and Marion Weldon co-star in this classic Western from prolific director Sam Newfield.