As Louise Holden is traveling to her grandfather's, her stagecoach is robbed by a group of road agents. During the robbery, a gunshot is fired and the stage takes off, with only Louise inside. She is rescued from certain death, however, by one of the highwaymen. Later, undercover agent Johnnie Taggart arrives in town, where he resumes acquaintances with Kitty, a dance hall hostess he once jilted in New Orleans. After she tells Johnnie that she owns the "Bullwhip" saloon with her partner, Clay Curtwright, he confides that he is a wanted man, now using the alias of Ace Braddock. When Johnie's friend Andy also shows up in town, Kitty suspects the two of being involved in the stagecoach robbery. After a posse fails to find Louise, she is discovered by Clay, who then delivers her to her grandfather, Judge Holden. Although he expresses his gratitude for Louise's safe return, Holden refuses to allow Clay into his home, explaining to Louise that Clay is an undesirable. Later, Johnnie meets with Holden, who tells the U.S. Marshal that his assignment is to stop the road agents before the local ranchers form a vigilante group. The judge also tells Johnnie that he suspects Clay of being the outlaw leader, but has no evidence against the saloon keeper. After defeating Ben Borden, a local ruffian, in a bar fight, Johnnie is offered a position in the outlaw gang, unaware that Clay has learned of his true identity from the naïve Louise. During a bank robbery, Johnnie is knocked unconscious while Ben shoots Jake, the night watchman, then frames the undercover agent for murder. Johnnie is saved from a lynch mob by Holden, who insists that he be given a fair trial. Clay has Holden disqualified for the trial, however, so Andy and Kitty break Johnnie out of jail. Wounded in the escape, Johnnie hides out at the judge's home. Without access to the law, Holden calls a meeting of the vigilante ranchers at his ranch. A lovestruck Louise, however, tells Clay of her grandfather's plan, who promises to elope with her after dealing with a few "business affairs." Clay then makes plans to ambush Johnnie and Andy on their way to the vigilante meeting, unaware that Kitty is eavesdropping on his discussion. Kitty sends Louise to stop the crooked saloon owner from murdering her grandfather and the others, but Louise is accidentally killed by Ben. Clay and Ben race back to town, only to learn that Kitty has taken all the saloon's cash out of the safe and placed it in the bank. When the vigilantes arrive and attack the "Bullwhip," Ben tries to use Kitty as a shield, but is shot dead by Johnnie. Clay is also killed while Kitty is successfully rescued from a broken balcony after she forces Johnnie to propose to her.