Finishing a trail drive, Hoppy and the boys head to town and immediately get caught up in the conflict between school teacher Miss Abott and next door saloon owner Mawson. When Miss Abott disappears, Hoppy gets a clue to her location and rescues her from Mawson's cabin. It looks like Mawson is the man he wants, but Hoppy finds an item that indicates otherwise.
William BoydHopalong Cassidy
Andy ClydeCalifornia Carlson
Rand BrooksLucky Jenkins
Anne O'NealMiss Abott
John ParrishSteve Mawson
Cliff ClarkDink DavisHelen ChapmanLola
Earle HodginsSheriff
Herbert RawlinsonGroves
Don HaggertyLippy
Lee Garvin has eloped with the daughter of a railroad man who didn't approve of the marriage. Hoppy steps in when the young man is framed for murder.
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.
When Ranger Hoppy's falsely accused young ranger friend is killed while supposedly trying to escape from jail, Hoppy is blamed and drummed out of the Texas Rangers.
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.
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.
Hoppy, California and Lucky arrive at a remote inn, where Lucky expects to be married - but finds the bride-to-be in distress over her uncle, who has suddenly disappeared from the inn. Then Hoppy finds the uncle's body in the shaft of his nearby mine...
Hoppy, California and Johnny partner up with brother and sister ranch owners, two of several who are having their access to water blocked by a dam owned by a greedy merchant in town, who is intent on driving them out and taking their land for himself.
One of Hoppy's Bar 20 ranch hands is tricked into participating in nefarious activities after being subjected to hypnosis.
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 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.
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.
Hoppy and his pals arrive in a remote town to investigate the counterfeiting of both U.S. and Mexican money; his only clues are the name "Mordigan" and a drawing of a comet. He quickly finds out that Mordigan is the town "boss"; but what or who is "the comet", and why are Mordigan and his henchmen intent on persecuting a young woman, her drunken brother, and her deathly ill sister-in-law who've also just arrived in town?