In 1866, Kansas, the American civil war has just finished and the armies disbanded. The building of the West begins, and in 1872, the new city of Dodge City is ruled by violence and shootings. The Irishman Wade Hatton (Errol Flynn) is a man adapted to these days and presently is conducting a group of pioneers, including Abbie Irving (Olivia de Havilland) and her reckless brother, to Dodge City. Once in the city, Wade is invited to be the local sheriff, and an incident makes him accept the position. He tries to clean up the cattle town, ruled by the powerful outlaw Jeff Surrett (Bruce Cabot) and his gang, with the support of the decent local people.