The Cartwrights' friend, Jim Acton, is in danger of losing his prized mare. He has sold a herd of wild horses to horse trader Sam Whipple, and Whipple takes him to court claiming the mare was part of that herd. Acton walks out on the court proceedings, and the judge awards the mare to Whipple. When Acton tries to make a deal with Whipple to buy her back, Whipple shoots at him. Jim kills Whipple in self defense and becomes a wanted man. The Cartwrights are sure he is innocent, but an overzealous deputy under Sheriff Coffee, has other intentions. Acton has only one wish: to run free like a wild horse.