Night riders are terrorizing homesteaders, and the town doctor tries to keep the locals from forming a vigilante group. After more towns people are killed, however, the rest of the town makes the doctor the town sheriff and tells him to clean up the gang.
A crooked real estate manipulator sells worthless land on mortgage to flood refugees, then tries to profit by reselling the land to the state, committing murder in the process, as the Three Mesquiteers work to bring him and his gang to justice.
Dan Ward, reformed and last member of an outlaw family, meets Molly Clark in a rocky draw near town. Ted Wells, a henchman for Dan's enemy Jim Swain, attempts to shoot Dan but is outdrawn and killed by the latter. Molly disappears and Dan learns that she and Wells had ridden there together. Sheriff Bob Larimer tells Dan that Molly is in love with Bert Gilmore and tried to have him ambushed. Dan takes a risky job with mine owner Pember of getting the $10,000 payroll through to the mine. Swain suspects that Dan is carrying the payroll, but his gang is unable to stop Dan. Betty Pember disregards Dan's warning that the hills are filled with Swain's men and she starts for town. She is kidnapped by Gilmore and Molly and Dan ride to her rescue.
Ace Beldon is in prison, but with his stolen bonds not recovered, Capt. Saunders has an idea. He sends Graham to prison and has him and Beldon break out. With Ranger Raymond assisting, they make their escape and get to the hangout run by Stone. But the plan starts to go awry when Sam overhears Graham talking with the Captain and reports back to Stone.
Jim Waters arrives at Ed Parks' ranch to find Parks' cattle herd mysteriously increased. Hamp Harvey has been losing cattle and he suspects Parks. But the culprit is Harvey's foreman Brent who gets his orders from the town's leading citizen Sig Barstell. Barstell wants Harvey's ranch and after trying to frame Harvey by killing Parks, Waters takes over and goes after both the killer and the rustlers.
When he swaps horses with the Tombstone Kid — a wrongly accused man on the run from the law — singing cowboy Tex Randall gets arrested by the local sheriff in a case of mistaken identity.
There is a range war between the ranchers led by Tilden and the outlaw gang of Link Carson. Wanted outlaw Dude Ramsey arrives and joins up with Tilden. First he saves the ranchers from Carson's trap and then exposes Pearson as Carson's informant and killer of Steve Warner.
Unable to legally capture and sell a herd of protected wild horses, corrupt rancher Rance Macgowan uses his trained killer horse, Volcano, to substitute for the real leader of the herd and cause havoc and death among the ranches. With the government about to drop the restrictions on rounding up the herd, the Three Mesquiteers find themselves in the middle of the controversy after their friend, Sheriff Miller is killed by Volcano.
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.
Brett runs a protection racket for an unknown boss. When Jeff Hayes arrives and opens a gambling den, they try to shut him down. Unlike the others who have given in, he plans to fight back.
A lawman poses as an outlaw, steals $10,000 from a cattle thief, then promises to return the money if he can join the gang--while finding a way to expose them.
Tex and sidekick Grass join McGill's traveling show. When Price has McGill's wagons burned, Tex becomes the county tax collector to earn money. This leads to trouble as one of those owing money is Price who says he will not pay. Business doesn´t go as plan.
When silver is found in Virginia City, Lawyer John Storm leads a group from Indiana west. He soon has to defend them all in court against a company that is after their claims. Fighting a crooked Judge, he gets a mis-trial by telling how much each of the jurors was bribed. Then he gets the Governor to appoint a new Judge. But just as the retrial opens, the Judge learns his daughter has been kidnaped.