Two young horse traders guide a Mormon wagon train to the San Juan Valley and encounter rugged terrain, the cutthroat Clegg gang, hospitable Navajo, and moral challenges on the journey.
When three Texas Rangers try to investigate kidnapped Mexicans being used as forced labor in the mines of Silver Bullet, they are framed for murder by the town's corrupt sheriff.
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.
When he runs for sheriff, Hoppy is beaten by Jerry Doyle, the gutless wonder voted for by every crook in town. When Hoppy moves to have the new sheriff impeached, outlaw leader Tad Hammond hires forty gunslingers to stop him. Stop Hoppy? Hah!
Hoppy and Lucky have been called in to investigate a series of stage holdups. The robbers are taking gold from Colby's mine and Hoppy suspects it may be ex-outlaw Colby himself. When Speedy strikes gold, Hoppy borrows it and announces a gold shipment hoping to catch the gang and their leader.
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.
Sue Morgan gets Hoppy and his friends to join their expedition looking for Indian artifacts. Expedition leader Atwood makes a deal with nearby cattle rustler Morgan to loot the Indian treasures instead and sell them. Hoppy is on to their plan and pretending to leave follows them. Not only is he outnumbered by Morgan's men, but California has himself about to be sacrificed in an Indian ritual.
Before he was killed by Mark Foster's men, Bud Lawton willed part ownership in his ranch to Hoppy and his two pals. When the three arrive they find a fake posing as Lawton. When they expose the imposter, Foster gets the Sheriff to jail them for Lawton's murder.
As rustled cattle have mysteriously disappeared, Johnny sends for his friend Hoppy, Hoppy arrives and immediately suspects Dan Slack. Realizing his telegram about Slack was intercepted, he locks up the operator Lafe knowing he can escape. Tailing Lafe he finds a secret entrance to a mine and inside finds the missing cattle. But Slack's men also find him just as the cattle are stampeded through the mine shaft.
Hoppy is busy chasing stagecoach bandits who sing as they rob.
At the reading of his late cousin's will, California learns the estate will be divied among whoever remains of the seven relatives. With one already dead, another immediately murdered, and the Lawyer telling them the ranch is almost worthless, Hoppy investigates.
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 and new sidekick California Carlson head to California to help out Lucky Jenkins.
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.
Posing as a cattle buyer, Hoppy crosses over into Oklahoma where the Jordan brother's and their outlaw gang operate outside the law. After receiving an unfriendly reception when he finds them, he, California, and Johnny rustle their cattle and drive across the river into Texas. He hopes they will cross over to retrieve their cattle and then he can arrest them.
A young Eastern lawyer, seriously injured in a stage holdup, secures the help of Hoppy, California and Jimmy in completing his mission to his woman cousin's ranch in Texas. The ranch, as are others in the same area, is being plagued by a gang called the Night Riders, while the friendly local town lawyer is trying to cajole the cousin into selling out to him. Hoppy begins by arriving in the town, separate from his pals, all spiffed up and dandified, posing as the Eastern lawyer...
Hoppy, California and Lucky take refuge from a storm inside a supposedly abandoned church outside a ghost town, only to meet a young woman and her mother there, then find themselves surrounded by a gang of "workmen" intent on tearing down the church if they have to kill the five to do it.
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, Johnny and California go to Arabia to buy some horses. There they get involved with a sheik and a harem and a kidnapping plot.
Burton is after Clark's ranch. He gets the banker to refuse to renew Clark's note and then sends his men to rustle his cattle. Hoppy is Clark's new foreman and is on to Burton's scheme. But just as he learns of the rustling and is about to go after the gang, the Sheriff arrives and arrests him for hiding Johnny who has been accused of robbery.