Leach Kilgrain has a plan to gain control of all the ranches in Pecos. His unscrupulous Mayor Ewell boosts taxes higher than the ranchers can pay, and Kilgrain plans to buy the land cheaply at foreclosure sales. Ellen Brandon rebels and shoots the tax collector Fuller when he visits her father, Jeb Brandon. While running from Kilgrain's henchie posse, she encounters Wild Bill Boone, grandson of the famous Daniel Boone, and forces him to change horses with her. Bill rides into Pecos and Kilgrain, knowing his reputation as a gunfighter, offers Bill the job of tax collector, and Bill accepts with the intention of getting evidence against kilgrain and the Mayor. He wires his friend Cannonball to bring a large amount of money to Pecos. Bill marks the money and gives it to the Mayor, saying it represents taxes he has collected. Meanwhile, Cannonball has his own problems as he is pursued by twins Melinda and Matilda and he thinks they are the same girl. Bill, gets the evidence he needs when Kilgrain and Ewell use the marked money to further their plans.