In the Broken Saloon of El Dorado, two long-time comrades reunite under tense circumstances. Sheriff J.P. Harrah (played by Robert Mitchum) welcomes his friend Cole Thornton (portrayed by John Wayne) with a rifle aimed at him. Their friendship has endured since the American Civil War, but there are clouds hovering over their camaraderie. J.P. is concerned about Cole's recent employment by the nefarious Bart Jason (Edward Asner), a man with an elusive fortune made in questionable ways.
J.P. explains the backstory of Jason, who arrived with wealth during the post-war period, needing resources that are currently owned by Kevin MacDonald (R.G. Armstrong) and his family, who have worked tirelessly for years. MacDonald is unwilling to sell, putting him in the crosshairs of Jason's greedy pursuits. As they converse, saloon owner Maudie (Charlene Holt) enters, joyously reuniting with Cole, which draws contrasts between her past and present affections.
Cole decides to confront Jason, only to find himself embroiled in tragedy. As he rides into the hills, he stumbles upon Luke, MacDonald's youngest son, who inadvertently fires upon him due to a misunderstanding. In a momentary lapse, Cole defends himself and fatally wounds the boy, who in agony, tragically takes his own life. Guilt weighs heavily on Cole as he returns Luke's body, and tensions with the MacDonald family escalate, particularly with Luke’s sister, Joey (Michele Carey), who attempts to seek revenge.
As Cole makes his way to safety, he is ambushed by Joey, who retaliates out of grief. Wounded, Cole seeks refuge at Maudie's, where Doc Miller (Paul Fix) hastily treats his injuries. Convinced he needs a better surgeon, Cole eventually decides to leave El Dorado. However, his journey leads him to a nearby town, where Mississippi (James Caan) seeks vengeance against the men who killed his mentor in a fierce showdown.
As the conflict escalates, Cole becomes entwined with Mississippi and engages in a series of confrontations against Jason's men. With the aid of camaraderie and strategic planning, they devise a plan to rid the town of the antagonistic forces surrounding Jason. Amidst gunfire and treachery, J.P., buoyed by newfound resolve and sobriety, joins forces with Cole and Mississippi.
The climax unfolds with dramatic gunfights and narrow escapes, leading to a pivotal moment where Cole confronts Nelse Macleod (Christopher George) in a tumultuous showdown. When the dust settles, Cole, J.P., and Mississippi emerge, scarred yet victorious. In a moment of personal triumph, Cole acknowledges Joey's bravery and sacrifices, while J.P. refinds his dignity as they both limping walk into the next chapter of their lives, back into the streets of El Dorado, stronger than before.