Retired wealthy sea captain Jim McKay arrives in the Old West, where he becomes embroiled in a feud between his future father-in-law, Major Terrill, and the rough and lawless Hannasseys over a valuable patch of land.
Rancher William Norton refuses to sell his cattle for half price, so saloon owner and gang leader Jim Fletcher, contrary to the orders from his secret boss Willard McGowan, the town banker, has his men rob and beat up Norton. Unknown to anyone, Marion, McGowan's adopted daughter is really the daughter of Norton, who disappeared as a young baby when she and her mother were passengers on a stagecoach held up by McGowan. Chuck Saunders, Norton's foreman, goes after the gang for robbing his boss and eventually uncovers the truth regarding Marion's heritage.
Steve Packard is the ne'er-do-well son of an Arizona ranching baron. Upon his father's death, Steve returns from his days as a South Pacific beach bum to protect his father's estate, which has fallen into the hands of Steve's estranged grandfather. The grandfather's foreman, Joe Blenham, attempts to wrest the ranch from Steve's rightful inheritance, whether the means are legal or not.
Down-and-out cowhand Jim Garry is asked by his old friend Tate Riling to help mediate a cattle dispute. When Garry arrives, however, it soon becomes clear that Riling has not been entirely forthright. Garry uncovers Riling's plot to dupe local rancher John Lufton out of a fortune. When Lufton's firecracker of a daughter, Amy, gets involved, Garry must choose between his old loyalties and what he knows to be right.
A scheming tobacco farmer sets out to ruin his competition by diverting the local water to his own property.
Following a killing and robbery in a big city back east, gang leader Kedge Darvas and some of his henchies take a train to a small western town in Idaho, with intentions of hiding out there until things cool down back in Chi or NYC, or wherever they lammed from.They are welcomed with open arms by the citizens under the impression they are there as capital investors with money to spend. Before long, Darvas figures the town is ripe for the taking and sends word for reinforcements, and each arriving train unloads a few suits and snappy-brim hats.Then they get rough, kill Sheriff Posey Meed and rile up the citizens, led by cowhand Brad Farley, who had Darvas spotted for a wrong number just by the way he made moves on Sue Vancey.
Tom Kenyon and his sidekick Pierre La Farge are hired by rancher Mike O'Day who, with his daughters Toni and Sugar, provides wild horses for the government remount station.
Hoppy's friend Dennis owns a rich gold mine. Frazier who owns the adjoining mine and wants the Dennis mine, has Dennis killed. Hoppy steps in to take over running the Dennis mine and learns Frazier's men sneak into and work the Dennis mine at night. Hoppy captures one of Frazier's men only to be captured in return by Frazier and left to die in a burning building.
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.
Escaped criminal "The Fox" hates Hoppy and a Rurales colonel for imprisoning him and lures Cassidy to Mexico in order to exact his vengeance.
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.
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.
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.
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.
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.
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.