Bart Jason, a wealthy cattleman with a dubious reputation, brings Cole Thornton (John Wayne), a gunslinger-for-hire in post-Civil War Texas, to the town of El Dorado. Bart is in need of Thornton’s sharp shooting abilities because he intends to strong arm the deeds to the local watering holes away from the MacDonald clan, who had legally staked their claims two decades prior.
JP Harrah, Thornton’s old pal and the sheriff of El Dorado warns him of the nefarious job. However, before Thornton can get himself free and clear of the local range war, he takes the life of the youngest MacDonald son, in an act of self-defense. The MacDonald’s only daughter, Joey, then shoots Thornton in revenge.
Thornton spends the next six months traveling about Texas, trying to deal with the MacDonald clan shootings. While in the town of Sonora, Thornton encounters a young gambler by the name of Alan Bourdillion Traherne, who is seeking revenge for the murder of his friend and mentor.
The young man, who goes by the nickname of “Mississippi,” draws immediate attention to himself by not only wearing a black witch doctor’s hat, but he avenges his friends death by throwing a knife from his coat faster than his opponents can draw a pistol.
Thornton and “Mississippi” strike up a fast friendship, before sharing a drink with another well-known gunslinger-for-hire, Nelse McLeod. McLeod informs the duo that Bart Jason hired him to do the job in El Dorado, and that he turned it down. Also, McLeod enlightens Thornton to the fact that Sheriff Harrah has a broken heart, and is drowning his sorrows in a whiskey bottle on a full time basis.
Cole and “Mississippi” make their way back to El Dorado to help the liquored up Sheriff Harrah and the MacDonald clan in their feud with Jason and, his new hire, McLeod. Harrah find his sobriety with the help of Deputy Bull, Joey MacDonald, and Cole’s old girlfriend Maude. He sobers up just before the streets of El Dorado fill with gunfire.
Thornton, whose gunshot wound temporarily paralyzes him, manages to outthink McLeod, and shoot him before Jason’s hired hand has a chance to pull his pistols. Joey MacDonald saves Cole’s life by shooting Bart Jason dead, who had his gun sighted on an already injured Thornton. After the final battle, the town of El Dorado is peaceful and everyone lives happily ever after.