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.
Hoppy is busy chasing stagecoach bandits who sing as they rob.
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.
Hopalong Cassidy and Johnny Nelson ride to the mountains to help a man and his daughter save their logging business from someone who is sabotaging their efforts.
A banker is trying to cheat people out of their silver-rich land. Hoppy learns that the banker is in league with an outlaw gang.
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.
Three bodies turn up in a frontier hotel. Hoppy solves the murders and chases the killers through unusually misty and dark locations.
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.
Hoppy is leading a scientific expedition and the Chinese who have a hidden settlement nearby are trying to stop them. Saulters and his outlaw gang are also in the area looking for a gold mine. When Saulters men attack, the gold mine is found. Hoppy agrees to file for the Chinese and heads after Saulters in the chase to the land office.
Hoppy's ranch is threatened by rustlers. Hoppy and the gang oblige as usual.
Hoppy, California, and Lucky travel to Mesa City for a short vacation. California buys new clothes and carrying his old ones in a suitcase, bumps into escaping bank robbers in the dark. His suitcase gets switched with that of the robbers and he is seen with the money. Hoppy must find the money that has mysteriously disappeared and also the robbers so that he can clear California who is now in jail.
A gang of outlaws are using force to become possessors of every ranch in the area. Hoppie, of course, is out to stop them.
A bad guy has used several murders to drive all the inhabitants out of town in order to give his gang access to the oil which lies under the land.
Hoppy, Lucky and California are chasing cattle rustlers who have been bothering cattle rancher friends of Hoppy. A crooked foreman is the source of the trouble. Johnny and Lucy are the love focus.
Julie's husband has been murdered and land agents want her to sign away her property rights. Hoppy warns against this but she does so anyway. It looks as though she will be unable to deliver the timber called for in her agreement. Hoppy has to make the lumber deal happened and solve the murder.
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.