A horde of hooded riders who terrorize farmers and ranchers find Tom Wilson riding alone on his buckboard and shoot him. Their leader, Blackie Devlin, takes a deed from Wilson's wallet. Tex Martin and his sidekick Stubby, on their way to take jobs awaiting them in another town, find Wilson, who is an old friend of Tex and his father. Before Wilson dies, he tells Tex that the Masked Riders killed him and asks him to help his partner, Dan Farley, to save their mine. Tex and Stubby go into a saloon at nearby Red Eye to ask directions to the mine. Blackie, who has given the deed to his superior Norton, tries to intimidate Tex, but Tex knocks him out, and Stubby holds off others by drawing his gun. Sheriff Walker arrives, and after Norton blames Tex for the fight, the sheriff warns Tex to stay away from the mine, where, he says, there have been fires, shootings and killings. Tex and Stubby disregard the warning and ride toward the mine, where, after they elude the sheriff and his men, Wilson's daughter Nancy aims a gun at them. Tex tells her about her father's death, and she takes them to meet Farley, who says that Wilson was on his way to mortgage the property to buy new mining equipment. Farley professes that the ore is only worth enough money to earn them a living. When the Masked Riders attack the mine, Tex shoots one before they ride off, and Nancy is shocked to discover that the man is her foreman, Bill Dawson. Farley gives Dawson whiskey to revive him, but he dies. In town, the citizens decide to band together as a vigilante force and ask Tex to be their leader. Blackie tells Norton of their plans, and Norton calls a meeting that night of the Riders. When Tex sees Norton, Blackie and others leave the saloon at ten that night, he stealthily follows and joins the Riders wearing the hood he took from Dawson. He listens to Norton state that the "big boss" is pleased with their progress in taking over the ranches and mines of Red Eye, but that they must break up the vigilante group and get Tex. When they find that they have one too many men at the meeting, Tex escapes on his horse, White Flash. He returns to the mine, where the sheriff, seeing his hood, arrests him. After Stubby helps him to break out of jail, Tex gets the vigilantes together, and they capture the Masked Riders. Tex chases Norton to a hiding place among the rocks, where Norton retrieves a pouch with gold coins. The big boss shoots Norton to get the money, but Tex then struggles with the boss, as the sheriff rides up with Nancy. Tex reveals the big boss to be Farley and says that Farley gave Dawson poisoned whiskey so that he would not talk. Tex tells Nancy that Farley tried to drive her out to get control of the whole valley and that a mineshaft is connected with his hideout. Later, Tex, Nancy and Stubby sing as they ride together.