A circus is on the run from the law while dealing with romantic entanglements and internal struggles.
Hoppy and Lucky are headed to South America to deliver a heard of cattle. Bay guy Ralph Merritt gets in their way. For a while.
Hoppy and new sidekick California Carlson head to California to help out Lucky Jenkins.
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 goes undercover as an outlaw (which permits him, for once, to drink and be mean to children) to track down a bunch of outlaws operating along the border. Loco, the head bad guy, deflects suspicion from himself by pretending to be a moron.
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.
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.
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.
A crusading newspaper editor recruits his old friend Hoppy to take the job of Marshall in a town rife with vice and murder directed at helpless miners.
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.
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.
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.
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.
An evil ranch foreman tries to provoke a range war by playing two cattlemen against each other while helping a gang to rustle the cattle. Each cattleman blames the other for missing cattle. With the help of Bill Cassidy (Hop-along, because of an earlier bullet wound) and Johnny Nelson, the warring cattlemen join forces to do in the outlaws.
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.
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.
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.
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.
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.
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.