No relation to the 1950 John Ford classic of the same name, Rio Grande is yet another rubber-stamp Charles Starrett western from the Columbia assembly line.
An outlaw on the run assumes the identity of a dead man. When in his new identity he finds himself elected the mayor of a small town, he decides to go straight.
Knowing that is contains valuable helium gas, a gang of bad guys first tries to purchase the ranch which Gene straw-bosses. When that fails, they lay a hidden pipeline to snag the gas.
Using a conventional Western story with an all dwarf cast, the filmmakers were able to showcase gags such as cowboys entering the local saloon by walking under the swinging doors, and pint-sized cowboys galloping around on Shetland ponies while roping calves.
Chasing jewel thieves, Captain Carson and Magpie head for the border where Carson, posing as a Chinaman, opens a store that buys jewelry. To flush the thieves into the open, Carson wins all their money at poker. They agree to sell him the jewels but plan to kill him and keep both the jewels and the money.
The Mesquiteers capture a horse thief who escapes justice through a crooked judge. They gather signatures urging the governor to investigate but a friend with the petition is murdered. Stony is accused.
Mary Smith decides after a lifetime of being a shut-in to do something wild while her father is out campaigning for the presidency, so she takes off for the family's home in West Palm Beach and inadvertently becomes romantically entangled with earnest cowboy Stretch Willoughby. Neither the dalliance nor the cowboy fit with the upper class image projected by her esteemed father, forcing her to choose.
Jack has been called in to investigate stage robberies where the stolen gold bullion mysteriously disappears, He finds the Professor, an elderly ex-con, and convincing him they used to work together, gets the Professor to get him in to the gang. Now posing as an outlaw, he learns what the Professor does with the bullion, but he is in trouble when his true identity is revealed.
In South America anything can happen: the consul might give you as a snack to the sharks, you can wind up as a working man (slave) in a banana plantation or as a recruit in the governor's navy. And there's always a fire squad waiting for you so you 'd better start a revolution! It takes all Fernandel's talent to go through this eventful journey.
Marshal Jeff sends for his friend Whit Gordon to help bring law and order to Tombstone. Bull and his gang with the help of the Sheriff and the Judge control the town. After foiling Bull's attempt to stuff the ballot boxes, newly elected Marshal Whit and his pals head to the corral for the showdown with Bull and his men.
Ore shipments are being stolen and the Rangers send Buck and his men to guard the next shipment. When that is stolen also, Buck is kicked out of the Rangers.
Tex returns to Santa Fe to find his Mother murdered. Foster runs the town and all crimes committed by his gang are blamed on Rogel and his men. He makes Tex Marshal but this backfires when Tex enlists Rogel and his men and goes after Foster who he now knows is responsible for his Mother's death.
Lightning Carson's nephew has been falsely accused of murder. To get in with the gang, Lightning poses as a Mexican. He also appears as himself making his costume changes at his sister's ranch. Just as he about to bring in the gang, a henchman finds evidence of his masquerade and arrives to expose the hoax.
Gene takes care of three tough kids sent west from Chicago after their father died and left them a cattle ranch. They help him catch a bunch of rustlers.