Hoppy frightens an outlaw gang by writing in prominent places the code numbers 3-7-77, the symbol of a band of vigilante terrorists.

Hoppy and Red help the U.S. Immigration Service investigate the deaths of smuggled Chinese aliens.

Hoppy steps in when a notorious outlaw tries to force his honest father and brother to help him collect the reward for his own capture.

Hoppy encounters bank robbers who are trying to recover the loot they hid in an old wagon inside the Twin Rivers livery stable.

Assigned to guard the workers building Arizona's first telegraph line, Hoppy learns that a supposedly retired man who owns several stores will lose a fortune if the line is completed, and uses wiretapping to foil a sabotage scheme.

A fast-shooting woman marshal interferes with the efforts of Hopalong Cassidy and his sidekick Red Connors to track down the bandits who stole a shipment of Army rifles.

Hoppy and Red hide an innocent young Mexican from a lynch mob and then go after the murderer who framed the boy.

Hoppy helps an old settler and his son fight a land grabber who's determined to take over their ranch.

As they ride into an apparently deserted town, Hoppy and Red are shot at, and then discover the town's only resident, also shot and left for dead.

When Hoppy and Red try to conduct an honest election in outlaw territory, the outlaws retaliate by getting Hoppy's nephew into trouble.

Hoppy tries to help a young Mexican laborer whose knife was found in a banker's back.

When a Mexican rancher accuses an innocent man of murder, Hoppy uses a black sombrero to clear the frame-up victim and save a wealthy young heiress.

Hoppy tries to help an ex-convict, hoping to go straight, who is being blackmailed into joining a plot to rob the Cattlemen's Association.

A blind Mexican woman asks Hoppy to help her fugitive son, who's been falsely accused of murder.

Hoppy and Red try to settle a dispute between cattle ranchers and sheep grazers.

Hoppy uses a health tonic to prove the innocence of a convicted murderer and the guilt of the real killer.

Hoppy tries to clear an old prospector who's been found in possession of the gold stolen in a train robbery.

Hoppy helps an old prospector whose discovery of gold has earned him several new friends and enemies.

Hoppy and Red are trapped in a burning house by a lovely young woman who has robbed a bank while posing as an old lady.

Hoppy and Red discover that two outlaws have ambushed the sheriff of Stone Valley and determine to help the local ranchers against an exploiter who wants to take over the valley and sell it ti the cavalry.

Hoppy fakes amnesia in an attempt to save the cattlemen's bank and the local ranchers from ruin springing from an embezzlement.

Hoppy poses as a cattle buyer in order to break up a ring of thieves who are stealing gold from a smelter.

Hoppy tries to prove that a gypsy boy's dead father was not a thief so that the boy can marry his sweetheart.

Hoppy risks death to convince the family and friends of vanished rancher Tom Murdock that his ghost has not returned from the dead to haunt them.

Hoppy steps in when the nephew of a contractor building a railroad is killed and all the construction plans stolen.