A posse discovers a trio of men they suspect of murder and cow theft and are split between handing them over to the law or lynching them on the spot.
When Sheriff Jake sees a man at the safe and then finds the payroll gone, he trails him. Just as he is about to arrest him, the man saves his life. Still suspicious, he joins up with the man and later they learn that Melgrove, the towns leading citizen, is trying to take over the area's ranches by having his gang stop all incoming supply wagons. With the ranchers about to sell to Melgrove, the two newcomers say they will bring in provisions.
Buck Peters arranges for Hoppy, California, Johnny and other cowboys to go to the aid of friends whose cattle are being rustled. Hoppy and California locate the rustlers' hideout and join the gang by posing as outlaws themselves, but must find a way to let the rest of the posse know where they are.
Hoppy, California and Johnny come to the ranch of a friend and his daughter, disguised as dude detectives from the east, to investigate the disappearances, without a trace, of several herds of cattle.
Hoppy goes undercover as a gambler from the East when Bar 20 cattle are stolen by unknown rustlers. Brennan/Talbot are twin brothers (one a casino owner, the other a rancher) and Hoppy believes they provide alibis for each other while one is out committing crimes. Hoppy gets a job in the casino to learn more but is exposed when a gambling gunslinger notices him.
An evil gang is involved in both cattle rustling and the robbing of stagecoaches. Hoppy must stop them without help from the sheriff who turns out be a major outlaw himself.
Hoppy goes to town to help Marshal Windy with some rustlers and winds up helping the widow Joyce when confidence men try to take her herd. King's Men songs include: "Hi Thar Stranger" and "Lazy Rolls the Rio Grande."
Hoppy, Johnny and Windy are fighting a malicious gang trying to stop a cattle drive from reaching a drought-stricken North.
Billy the Kid and his pal Fuzzy escape from the Marshal and find themselves in the ghost town of Laramy. The city was abandoned because of Sykes and his gang, who are in search of a gold mine.
Bolton has organized a feud between the Rork's and the O'Neil's. He has rustled cattle and killed a man putting the blame on Danny O'Neil. Tom Rork has found a bullet with markings on it that he hopes will clear Danny and bring in the real killer.
US marshal Len Merrick saves Tim Keith from lynching at the hands of the Roden clan, and hopes to get him to Santa Loma for trial. Vindictive Ned Roden, whose son Ed was killed, still wants personal revenge, and Tim would like to escape before Ned catches up with him again. Can the marshal make it across the desert with Tim and his daughter? Even if he makes it, will justice be served?
A ranch owner turns his place into a home for boys who have lost their fathers in World War II. His evil female lawyer covets the ranch and uses a gang of local toughs, a pack of killer dogs, and a phoney rancher's beneficiary to get it. U.S. Marshal Rogers opens an investigation when the rancher is killed.
When Matt Kilgore and his men frame and then hang an innocent man, Lige Saunders sends for his son Wild Bill Saunders who arrives to find his father shot by Matt's brother. When the brother is killed in his fight with Bill, Matt sends two fake Deputies to arrest Bill whom he then plans to hang. But Matt's sister, attracted to Bill, overhears the plan and rides for help.
Lambert, a young man out to make his fortune, is out west trying to sell a gadget that can peel potatoes, open cans, pull out nails and perform other handy tasks. He comes to a cattle ranch and runs into a group of cowboys eating supper. He impresses the cowboys so much that they make him their leader, and it's not long before he's hired by pretty young ranch manager Vesta Philbrook as her aide and bodyguard. "The Duke", as he's now called, falls in love with her and sets out to help her get rid of a gang of vicious cattle rustlers that are constantly raiding her ranch.
Deputy Sheriff John Steele recruits bandit Sonora Joe to help him find out who's been bumping off all the local lawmen and rustling the cattle.
Sam is a parolee who has paid for his dirty deeds. Now determined to go straight and help take care of his hot headed brother and devoted sister, he becomes set upon by both the law, represented by Federal Marshall Rocky Lane, and by his former outlaw buddies led by the notorious William Oakes.
The first of a long-running series of Monogram-produced westerns starring Johnny Mack Brown and Raymond Hatton that replaced the Rough Riders series following the death of Buck Jones in the Boston night club fire. Though the next three years featured Brown (as Nevada Jack McKenzie) and Hatton (in his Sandy Hopkins role from the Rough Riders series) as undercover marshals in some form or another, this initial entry had Brown as a lone rider seeking vengeance and he and Hatton's characters were unknown to each other through most of the film. Hopkins offer McKenzie a marshal's job at the end of the film, which the Brown character declined and rode off alone on his quest. This quest didn't take long as by the next film in the series Nevada Jack McKenzie was a full-fledged U. S. Marshal.
Tom Evans (Jon Dawson), nephew of U.S. Marshal Sandy Hopkins (Raymond Hatton), has just trailed his cattle to Yucca City, where he intends to sell to Ben Crowley (Harry Woods), owner of practically everything in town.Tom loses his money in a crooked game ran by Crowley. "Nevada Jack" McKenzie (Johnny Mack Brown), a U.S. Marshal working undercover, watches the game and secures one of the "fixed" decks of cards. Later, Tom discovers Crowley's men rustling his cattle and is shot. Nevada finds him severely wounded and hides him with Jeff Lewis (Sam Flint) and his daughter Mary (Ellen Hall). Sandy, posing as a dentist, arrives in town after a wire from Nevada. The latter confronts Crowley with the crooked deck and also with the fact that Tom is still alive, and demands a partnership from Crowley. When Crowley learns that Lewis is hiding Tom, he decides to have both Tom and Nevada killed.
Stodge City is in the grip of the Rumpo Kid and his gang. Mistaken identity again takes a hand as a 'sanitary engineer' named Marshal P. Knutt is mistaken for a law marshal. Being the conscientious sort, Marshal tries to help the town get rid of Rumpo, and a showdown is inevitable. Marshal has two aids—revenge-seeking Annie Oakley and his sanitary expertise.
At the height of the frontier era, a train races through the Rocky Mountains on a classified mission to a remote army post. But one by one the passengers are being murdered, and their only hope is the mysterious John Deakin, who's being transported to face trial for murder.