Theodore Roosevelt travels to Bismarck to attend the murder trial of his old rival, the Marquis de Morés. Back in the Badlands, the Marquis' wife, Medora, is visited by her father, who tries to convince her to leave her murderous husband.

When Theodore Roosevelt assists a Sioux brave in finding his stolen horses, they help identify a notorious horse thief. Though found innocent of murder, the Marquis de Morés must still repair his damaged reputation with his father-in-law.

A Chicago cattle baron sends two enforcers to make deals with Medora's cattlemen, leading to a deadly confrontation with the Marquis de Morés. Sensing trouble, one of Theodore Roosevelt's Elkhorn men heads off to Montana to find some help.