In 1870, dedicated, self-styled soldier Joan Randall forms a group of Confederate sympathizers to establish the Republic of South Kansas. Determined to regain land that she believes the U.S. Government stole from her and her followers, she raids towns to confiscate government goods. Although Joan firmly orders that no civilians be hurt, her regulations are countermanded by her second-in-command, Colonel Jedcott, who allows the soldiers to pillage the town of Lincolnsville after Joan has met with her secret contact, bar owner O'Leary, and left. The destruction of Lincolnsville results in the establishment of a $10,000 reward for her capture or death. Fort Franklin commander General Frank Hawthorne, assigns his best scout, the intrepid Jeff Connors, to capture Joan, and Jeff goes to Lincolnsville to search for clues. There he overhears outlaw Chet Dawson inquire after Joan, whom he is to meet, so Jeff arrests him. After deciding to impersonate Dawson, Jeff must undergo being branded with the notorious Sioux mark of a "squaw stealer" that Dawson bears. Jeff keeps Dawson's rendezvous with Joan, who accepts him after he saves her from being captured by the cavalry. Jedcott distrusts Jeff, however, and picks a fight with him, but Joan stops him when she sees the brand. At her secret headquarters, Joan shows Jeff the list of her contributors and then prepares to turn in for the night. Jedcott is furious that she is letting Jeff stay in the house with her, but she assures him that Jeff maintains he was falsely accused of being a squaw stealer. Meanwhile, Dawson has escaped from the fort and traveled to Joan's hideout, where he enters her bedroom. He is about to attack her when Jeff, who is searching for Joan's list, stops him. Jeff shoots Dawson before he can reveal his identity, and the injured man is carried away. The next morning, Dawson informs Jedcott of Jeff's identity, but Jeff manages to leave with Joan anyway. Joan is falling in love with Jeff, who realizes that although her actions are wrong, she honestly believes in her cause. As they talk while standing near a cliff, Dawson appears and tries to shoot Jeff. His shot hits Joan, however, before Jeff reaches him. Dawson is thrown off the cliff during the ensuing fight, after which Jeff rushes Joan to the fort. When she recovers from her injury, she is put on trial, and despite Jeff's pleas for leniency, she is sentenced to be hanged. Determined to save the woman he loves, Jeff rides to governor's office and receives a pardon from Joan, although the governor expresses disbelief that Jeff will reach the fort in time to stop the execution. Meanwhile, Jedcott, Dawson and O'Leary have taken advantage of Joan's capture by planning to steal her treasury. Aware that if Joan is pardoned they will have to account for the money, they capture Jeff as he returns to the fort. Jeff escapes by killing O'Leary and outrunning the others, and reaches the fort in time to save Joan. Jedcott and Dawson are apprehended, and Jeff and Joan ride off together to begin a new life in California.
