Sharpshooter and outlaw Calamity Jane is released from prison in order to catch renegades who have been smuggling guns to the Indians. She is ordered to Fort Deerfield, where she plans to join up with lawyer Jim Hunter and pose with him as a pioneer couple traveling West. Hunter is killed before Jane reaches him, but has left word for her to contact a friend of his named Hank Billings in the small town of Buffalo Flats. Jane is followed there, and makes a narrow escape with "Painless" Peter Potter, a timid, quack correspondence school dentist, whom she marries for the wagon train trip. Painless, completely oblivious to Jane's ulterior motives for marrying him, attempts to make love to her, but is met with a sharp thud on the back of his head every time he tries to kiss her. During an Indian attack on a pioneer camp, Jane deftly kills nearly a dozen Indians singlehandedly, but lets everyone, including Painless, believe he did the killing, hoping that the renegades will believe he is a federal agent. Meanwhile, in Buffalo Flats, Toby Preston, the renegades' leader, receives word that a new federal agent is about to arrive with the wagon train. When the wagon train pulls into town, Jane learns from Hank that two loads of dynamite came with them. Believing him to be the agent, Preston's men immediately attempt to get rid of Painless by ordering a saloon girl named Pepper to seduce him, thereby inciting the lethal jealousy of her boyfriend Joe. Painless talks tough and gives Joe until sundown to get out of town, and Jane decides to let him be killed in order to get rid of him. At the last minute, as Painless walks out into the street to meet Joe for a duel, Jane decides to save Painless in order to use him as bait, and shoots for him from a window, killing Joe. Hank later enters Jane and Painless' room with an arrow in his back and tells her that the dynamite is in the undertaker's parlor. Jane sends Painless after the dynamite, and he bravely holds up the renegades, but then is abducted by an Indian. He and Jane are then taken hostage at an Indian camp, where she confesses that she married him to aid her in catching the outlaws, but now loves him. Also at the camp is the white turncoat, Jasper Martin, whom Jane recognizes as one of the governor's aides. As Jane is tied to a stake and prepared for burning, Painless, transformed by Jane's love, rigs the dynamite to blow, and they escape. Later, as Jane and Painless leave for their honeymoon, she is pulled from the wagon by one of the horses and dragged off into the distance.