Gridley is mining silver from an old Mexican mine and bringing it into the USA thru a passage into his worthless mine. Border guard Rogers suspects Gridley and finally finds the secret entrance to the Mexican mine. He sends Lee Madison for help only to have her captured by Gridley. Trigger brings help that takes care of Gridley's men and now Roy has to rescue Madison.
Knowing the railroad is coming, Carter is after the rancher's land. Bob and Chito return just in time to save Banker Stockton and his money from Carter's men. When Stockton then lends the ranchers money, Carter has them burned out. Bob knows Carter is responsible and when Carter's henchman Saunders is recognized, Bob goes into action.
In this Roy Rogers entry, featuring a song written by Oklahoma Governor Roy J. Turner (making him and Lousiania's Jimmie Davis and Texas' W.E. "Pappy" O'Daniel possibly the only state governors to write songs used in a western), Flying U ranch owner Sam Talbot is killed by a fall from a horse. St. Louis reporter Connie Edwards comes to check a rumor that he might have been murdered. She goes to Roy Rogers, editor of the local newspaper, and he takes her to the reading of Talbot's will. The ranch is left to Talbot's 12-year-old ward, Duke Lowery, much to the dismay of Talbot's niece, Jan Holloway. After some attempts on Duke's life, Roy finally proves that Jan, Steve McClory and coroner Jim Judnick had Talbot killed and are conspiring to do the same for Duke, making Jan the last heir.
Buster Crabbe and Johnny Weissmuller battle it out in Cajun country! Johnny, a riverboat pilot on the Mississippi, is seduced away from his fiance (Carol Thurston) by a rich outsider (Virginia Grey) who's nursed him back to health after a serious accident. She owns a large piece of the swamp and has outlawed hunting on her property. His rival Mike (Crabbe) is a trapper who harbors deep resentment for Johnny and his new wealthy friends. When he feels Johnny is responsible for the hunting ban, he resorts to destructive acts of vengeance.
Rodeo star Roy Rogers returns home to find that his old friend Tom Craig has been murdered after he was accused of stealing a family crest from Helen Williams. Helen joins up with Roy and Gabby Whittaker to find the killers and the crest.
A young outlaw gets involved with a gang of crooks. When he tells them he is breaking away, they threaten to pin a false murder charge on him. But he is rescued and reformed by his sister, and an undercover agent for the express company.
During World War II, a young boy and girl, living with their respective families in an apartment house that had restrictions against pets, adopt a lost dog and hide it in a vacant apartment, which may have been the only vacant apartment in the United States at the time this movie was being filmed. A burglar breaks in and the apartment is damaged when the dog and crook have a tussle. This blows the dog's cover, but the kids enlist him in the K-9 Corps, and the dog distinguishes himself in the WWII Italian campaign
Roy Rogers rides to the rescue when a bank robber's orphaned son (Tommy Cook), who is living at a ranch for homeless boys run by Gabby Whittaker (George "Gabby" Hayes), attracts the attention his father's rowdy gang, who want to claim the boy's inheritance for themselves
Cutthroat pirate William Kidd captures Admiral Blayne's treasure ship and hides the bounty in a cave. Three years later, Kidd, posing as a respectable merchant captain, offers his services to the King of England. Seeking a social position, Kidd also negotiates for Blayne's title and lands, provided he can prove Blayne was associated with piracy. Launched upon his royal mission, Kidd is unaware that Blayne's son Adam is among the crew, determined to clear his father's name.
Insurance Investigator Roy is looking for Weston and the missing money he supposedly obtained in a robbery. When he catches him and listens to his story, he changes his mind about him. A freak accident locates the missing money box and they find the seal unbroken. Roy then announces the box will be opened at the showboat that evening.
A naval officer who had deserted several years earlier is drawn back to the Navy when World War II begins. He re-enlists under an assumed name, and is assigned to a minesweeper, where he has to perform hazardous duties while at the same time keeping his real identity a secret.
A man of no worth brags to his daughter back East that he is rich and owns a big ranch. When she decides to pay a visit to her father, Roy and his buddies agree to pretend that the poor man is the owner of the ranch.
A doctor and his staff in a hospital on the Philippine island of Corregidor shortly after the Japanese attack on Pearl Harbor try to treat the sick, injured and wounded as American and Filipino troops desperately try to beat back a ferocious Japanese attack.
Bad guys plot to trick a newly arrived Eastern girl out of a ranch which belongs to her infant ward. Roy, of course, saves the ranch for the girl. Songs include "I'm Headin's for the Home Corral," "He's a No Good Son of a Gun," "Sandman Lullaby," "Song of the San Joaquin," and "I'm a Cowboy Rockefeller."
Judge Kirby is being blackmailed and forced to let outlaws go free. He was once the partner of Roy's father and when Roy reads in the paper that he is in trouble he heads out to help him. Arriving, Roy quickly realizes he has been mistaken for one of the outlaws and is not wanted in town. However he stays, and now posing as that outlaw, hopes to learn who is causing all the problems.
A Nazi spy ring is after a chemical formula that increases the power of ordinary gasoline for U.S. Army aviation use. Two U.S. chemical companies are developing the formula, with each working on half for security purposes. The spies get half the formula and know that either of two chemists, Robert Norton or Tom Fielding, knows the rest. They capture Fielding, through a ruse by gang member Linda Pavlo, and threaten the life of his sister Nancy and his mother if he does not give them the formula. To protect his friend Fielding, who does know the formula and is engaged to Nancy, Tom pretends to know the secret and boards the Dawn Express plane with the spy leader and his gang.