In the dusty landscape of Sinola, New Mexico, around 1900, Joe Kidd, a disillusioned drifter with a past as a bounty hunter, finds himself imprisoned for the crime of hunting on sacred Indian land and disrupting the fragile peace. The entrance of the charismatic revolutionary Luis Chama, a Mexican bandito, triggers a monumental series of events as he incites a peasant revolt against the oppressive landowners who are ruthlessly stripping the poor of their ancestral lands.
Wealthy landowner Frank Harlan reacts swiftly by assembling a posse with the aim to capture Chama, but Kidd initially declines to join them. However, after learning that Chama's group has targeted his own ranch and one of his workers has been brutally attacked, Kidd reluctantly agrees to assist Harlan.
The posse, armed with the latest rifles, descends upon a village close to Chama's hiding place, compelling terrified villagers to seek refuge in the local church at gunpoint. Harlan issues a menacing ultimatum: hand over Chama within a set time— or face harsh repercussions, including the execution of five Mexican hostages. Kidd finds himself inside the church with the captives, his chance to help Helen, a mysterious hostage unknown to Harlan, jeopardized when he discovers that she is actually Chama’s beloved and one of the captured. Seizing a moment of opportunity, Kidd devises a plan for escape, utilizing his wits to slip away from his captors.
Navigating through the perilous landscape, Kidd seeks out Chama and his compatriots, employing both clever tactics and his physical skills to force compliance. He deceitfully asserts to Harlan and the posse that he will deliver Chama to Sheriff Mitchell, all while harboring his true intention to stand against their oppressive rule. As the posse pushes forward, determined to intercept a train en route to Sinola, they fall prey to the deadly aim of Mingo, the best marksman among them. In a twist of fate, Kidd has acquired a long-range rifle during his escape, which he uses with deadly accuracy to eliminate Mingo.
Upon arriving in town with the captured Chama, Kidd finds Harlan and the remaining posse members already scheming for revenge. Undeterred, Kidd focuses on executing his primary objective: presenting Chama to Sheriff Mitchell. He commandeers a steam train and drives it directly into the saloon, igniting a frenzied gunfight against Harlan's merciless gang. In a climactic confrontation, Kidd triumphs, vanquishing Harlan and his men in the courthouse where his ordeal began. At last, Chama is free, surrendering to Mitchell, while Kidd, restoring his own sense of agency, collects his belongings, delivers a well-deserved punch to the sheriff for past grievances, and departs from the town with Helen by his side.
