Dr. Bob Ridgeway is prevented from leaving the nearly abandoned mining town of Silver Creek after gunslingers Charlie and Piute Bill decide to duel each other. Bill wins the duel by shooting seconds before the appointed time, but a bullet grazes his shoulder. Bob attends to him and to bystander Beth Larabee, who was hurt by flying glass. Impressed by his skill, Beth tries to talk Bob into moving to her town, Las Mujeres, which is run solely by women, but Bob refuses. He bids goodbye to his friend, saloon owner Woody Callaway, and takes the next stage out of town. On the trail, however, the stage is ambushed by Beth, who takes Bob back to Las Mujeres at gunpoint. There, Beth's sister, singer Ellen, takes a liking to Bob, and Beth's boss, Iron Mae McLeod, insists that he stay. Mae, who has grown tired of being under the thumb of men, has taken control of the town and, along with her female employees, allows men into Las Mujeres only as workers or customers at her crooked gambling house saloon, the Paradise. Days later, outlaw Frank Slater visits Mae to ask her one last time to work as his partner by providing information about area banks, but she refuses, stating that she eventually gets everyone's money at her saloon. Angry at his failure to seduce her through romance or money, Slater warns Mae that she will soon be sorry. Meanwhile, Ellen attempts to seduce Bob, who is more attracted to the slightly demure Beth. As the weeks pass, Slater engineers a series of local bank robberies. One day, he hears that all the money in the Silver City bank, including Mae's, will be sent by stage to Yuba City, and assumes that Mae will have information about the transfer. He goes to the Paradise to convince her to help him rob the stage, and there sees her with Woody, her old partner. Years earlier, Woody and Mae outsmarted fellow outlaw Sam Bass, but then separated when Woody decided to go straight. Woody now wants to take over the Paradise and make it a legitimate business, and proposes that they play one hand of poker with the saloon as the stakes. She refuses but does not kill Woody, prompting Slater to hypothesize that she loves him. Knowing that Slater is dangerous, Mae agrees to help him rob the stage, but then marshals her girls to plan a double-cross. She sends Beth to deliver a message to Slater, but when Beth gets to his hideout, only Bass, who has forced Slater to join up with him, is there. Bass attacks Beth but she breaks free and flees. Bass then meets Slater and his men, and together they plan their ambush of the stage. While they wait for the coach, however, Mae's gang steals the gold and brings it back to the saloon. Soon after, Beth staggers back to the Paradise and collapses. Bob tends to her, but Mae pushes him aside and insists that Beth give her information. As Mae plans to outfit all the women with guns against the probable attack by Slater and Bass, Bob chastises her for endangering the women in "a man's game," and refuses to allow Beth to join them. Mae ignores him but is soon distracted from her scheme when she hears that a marshal will be elected the following week in Las Mujeres. Woody informs her that women will not be able to vote and that he is bringing in his Silver City friends to vote for him. Defeated, she offers to play a poker game for control of the new marshal, but before they can finish the hand, Slater and Bass appear with their gang. A gunfight breaks out, during which Mae and Woody seal a partnership agreement with a kiss. Bob and Ellen stop Bass from stealing the money, but Ellen is shot in the process. After the gang is stopped by the Paradise employees, Mae holds Ellen's dead body and cries. The next week, she pleads guilty to charges against her but has her sentence suspended by Woody, the new marshal. She and Beth, newly married to Woody and Bob, respectively, then quietly exercise control over their unsuspecting husbands.