Cheyenne Jones comes to the Blue River Ranch and asks for a job as a cowpuncher. Actually, Jones's real name is Buck McCloud and he's the new owner of the spread, having inherited it when his uncle died a year earlier. He's roaming the range incognito while trying to identify who's behind the cattle rustling that is afflicting his new business.
Supernatural events on the range prompt an investigation by cowboy Brown in this western.
When his cattlemen abandon him for the gold fields, rancher Wil Andersen is forced to take on a collection of young boys as his cowboys in order to get his herd to market in time to avoid financial disaster. The boys learn to do a man's job under Andersen's tutelage, however, neither he nor the boys know that a gang of cattle thieves is stalking them.
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.
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.
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.
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.
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.
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.