California Gold Rush is set in 1849. Ryder heads to Sutter's Mill, where he must contend with claim-jumping and treachery.

U. S. Marshals Nevada Jack McKenzie and Sandy Hopkins come upon an overturned stagecoach with the driver and the passenger dead. They learn that the passenger, Hinkley, an archaeologist, has discovered an old Indian site that contains gold relics, and a gang has robbed him of the relics he was carrying. Jane Condon, daughter of Hinkley's partner who was also murdered, tells Nevada that an old Indian guide, Shag, is the only one who knows where the site is. The outlaws find Shag first, and kill him after forcing the information from him. Hinkley's son, Joel, arrives and knows where the site is and leads Nevada and Sandy there ahead of the outlaws.

Rangers Tex Haines and Dave Wyatt track a killer known as the Whispering Skull. In the wake of the Skull's slaughter, a band of thieves takes advantage of the fear he's brought to town.

Fur thieves, who murder trappers when they refuse to give up their pelts at a low price, occupy the attention of the Royal Northwest Mounted Police. The leader of the gang is Victor Renaud, also the mayor of the small Canadian town where the gang is headquartered. Lucky Kerrigan is broken from the mounted service for apparent disobedience to orders, which results in the death of a fellow Mountie. Lucky, working undercover, aids the Mounties in rounding up the gang and gains back his uniform, and also the love of Gabrielle Renaud, Renaud's sister who was unaware of his criminal activities.

Belle Langtry runs a town being taken over by cattle rustlers. She is also a front for the outlaws, who are led by Steve Fraser. Hoppy gets elected sheriff and cleans up the town with help from the Bar 20 boys.

Hoppy, Lucky and California search for a mine owned by Trudy Pendleton after it was taken from her by thw swindling gambler Ace Gibson. They find the mine and Hoppy fights Gibson over it.

A town bedeviled with outlaws sends for Hoppy, Lucky and California after their own vigilante committee fails to solve the towns problems. Hoppy discovers that the bad guys are led by the town boss, and so are the vigilantes.

Joe Weller has instigated a conflict over water rights between two ranchers. The idea is to have the ranchers do each other in then move in and take over. Hoppy and the good guys won't let this happen.

Stephen Westcott and Ed Martin scheme to put Jane Travers' wagon line out of business. They want to use it take over all the wagon- train traffic going west. Hoppy, California and Lucky must make sure that doesn't happen.

Hoppy and new sidekick California Carlson head to California to help out Lucky Jenkins.

European bad guy Baron Bendor leads some local townsmen in a plot to obtain horses through theft. Hoppy and his sidekicks Lucky and Speedy must find and expose the horse thieves.

Buck Colins heads a group of local ranchers who are trying to prevent the railroad from completing its line through their property. Till now they have been able to charge tolls on herds passing through. Hoppy goes undercover to expose them.

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.

Disguising himself as a milquetoast Easterner who writes Western novels, Hoppy enrolls in a dude ranch in order to unmask the murderer of the owner's husband.

The local school is causing Hoppy problems. First Bar 20 cattle are stolen when Hoppy investigates a problem there. Then the new teacher arrives and disrupts the routine of the Bar 20 hands. Later with the Bar 20 hands at graduation, the rustlers are poised to strike again. But there is dissension among them and this will lead to the break that Hoppy needs.

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.

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.

Belle Starr has returned from time in prison only to face a hail of bullets, along with rescue by Hoppy and the Bar 20 gang.

Hopalong Cassidy, boss of the Bar 20 ranch in Texas, rides down the Camino Real in the New Mexico cattle country near Alamogordo, in response to an urgent message from his lifelong sweetheart, Nora Blake, who is in serious trouble. Before he and his saddlemates, "Lucky" Jenkins and "Pappy", can reach her ranch, they are stopped by Clay Allison, a cattle-rustler who is in almost complete control of the district, and wants to extend his holdings by seizing Nora's cattle and driving her out. Seeing Cassidy as a menace to his plans, he has him arrested on a trumped-up charge. Cassidy and his pals shoot their way out of the trouble and reach Nora;s ranch where they learn that Allison's henchmen have murdered her foreman, Tom Dillon, and Allison has sent for a crew of outlaws on the Texas border.