Doc Lockwood and his gang are trying to take away Autry's contract for supplying horses to the stagecoach line. Parson Brooks joins Autry in an effort to clean up the town of Sadderlock.
At the close of the Civil War, a band of Southern guerillas disguised themselves as Union soldiers, the better to perform acts of sabotage in Utah. Autry plays a cavalry scout who goes after guerilla leader McQuarrie.
Not quite as memorable as his previous Riders in the Sky, Gene Autry's Sons of New Mexico is still well up to the star's standard. This time, Gene tries to reform Randy Pryor, a would-be juvenile delinquent, played by Autry-protégé Dick Jones (who later starred in the Autry-produced TV series Range Rider and Buffalo Bill Jr). To this end, Pryor is enrolled at the New Mexico Military Institute, where much of this film was lensed. The kid chafes at the school's regimen and escapes, heading back to his criminal mentor Pat Feeney (Robert Armstrong).
Gene Autry is back near the saddle, trying to help out a crippled jockey. Gene is certain that the jockey can ride in the Big Race if the lad can regain his self-confidence. Meanwhile, Gene and comical sidekick Sterling Holloway have another problem on their hands: A rogue stallion has "kidnapped" Gene's prize mare. Piloting a plane, Autry seeks out and locates the stallion.
Autry is drawn into the plot when he's given power of attorney in a property settlement involving his old pal and a gang of land swindlers. The pal then goes on an extended vacation, leaving Autry to sort things out.
Gene Autry heads a cattlemen's association and calls on the inexperienced Jim Agnew to negotiate the sale of five hundred heads of cattle. Jim ends up losing the cattle in a crooked poker game, however, and Gene and his sidekick Frog set out to find the cheating gamblers. It soon becomes clear that the leader of the gamblers is none other than Asa Lock, the dastardly father of Gene's romantic interest Stephanie.
When his well-meaning sidekick (Smiley Burnette) buys a cow farm instead of a cattle ranch, singing cowpoke Gene Autry prepares to embrace the dairy business. But with a corrupt association bent on driving up milk prices, it's up to newly elected Sheriff Gene to clean up the mess. Country music icon Patsy Montana sings "I Want to Be a Cowboy's Sweetheart," while radio crooners the Texas Rangers perform alongside Autry.
The Colonel sends Fred Dawson and Doc Flanders to investigate a cattleman sheepman war. Posing as a two man medicine show, they quickly become involved. When Fred tries to bring the two sides together, Joe Allison is shot and Fred blamed. With Fred in jail and a lynch mob on the way, Doc tries to break his friend out.
When shifty cattlemen Belknap (Walter Miller) and H.R. Shelby (Gordon Hart) are caught shipping infected animals to Mexico, they frame inspector Gene Autry. Now Autry and his sidekick, Frog Millhouse (Smiley Burnette), must catch the bad guys in the act and set things straight. June Storey co-stars as rancher Martha Wheeler. Autry sings "I'm Gonna Round Up My Blues," "Moonlight on the Ranch House" and "Big Bull Frog."
Young Joe is paralyzed as he is bucked by a wild horse, a strawberry roan. Angered, his father, Walt, tries to shoot the horse but is stopped by his foreman, Gene Autry. The roan escapes and Autry, told to leave the ranch by Walt, finds and trains the horse, now named Champ, in hopes that by returning it to Joe it will provide him with the will to overcome his disability.
Cavanaugh and McCauley are after the ranchers land. When the Government announces the land will be put up for auction, the ranchers pool their money only to have it stolen by Cavanaugh's men. They then plan to sell their cattle but Cavanaugh announces a fake gold strike and the cowhands all leave. But Gene's hobo friend the Judge says he will get the cattle to market and he sends out a signal to his hobo friends.
A Mexican bandit is about to be executed in the United States, so his brother takes over a train and holds the passengers as hostages unless his brother is released. Now both the Americans and Mexicans are baffled as to what to do. One of the passengers — who wrote the letter for their captor — has a suggestion: call mercenaries Hank Brackett and Johnny Reech. They do, and as expected they do come up with a plan, but the president of the railroad is not sure if it will work.
A group of homesteaders in 1875 are harassed by an evil, land-grabbing, gunslinging cattleman until a stranger with a mysterious past comes to their aid.