In the year 1913 Texas, we follow Pike Bishop, portrayed by William Holden, the leader of a weary band of outlaws who are eager to retire after one last heist. Their target? A valuable stash of silver from a railroad payroll office. However, their plans are sabotaged by the corrupt railroad agent Pat Harrigan, who enlists a posse of bounty hunters led by Pike's former partner Deke Thornton, played by Robert Ryan. This results in a violent ambush that leaves a significant portion of Pike's gang dead, alongside numerous innocent bystanders, as he cleverly uses a serendipitous temperance union parade to cover their escape.
The only survivors from this bloody encounter include Pike's steadfast companion Dutch Engstrom, portrayed by Ernest Borgnine, brothers Lyle and Tector Gorch, Angel, an inexperienced member of the crew, and a fifth man who, tragically wounded and blinded, Pike mercy-kills. To their dismay, they discover that the supposed treasure they have stolen is nothing but worthless steel washers placed there by Harrigan. In desperate need of funds, the gang decides to travel to Mexico, accompanied by the grumpy Freddie Sykes.
Upon crossing the Rio Grande, they reach Angel's hometown, where the village elder warns them of General Mapache, a ruthless Huertista officer from the Mexican Federal Army known for plundering local resources to sustain his operations against Pancho Villa's forces. Seeking work, Pike and his gang approach Mapache at his headquarters in the town of Agua Verde.
While there, Angel encounters his former lover Teresa in Mapache's embrace and, in a fit of rage, kills her, inadvertently putting the gang's lives in jeopardy. Pike, however, manages to pacify the angry general. Mapache proposes a scheme to Pike — to rob a U.S. Army train in order to replenish his dwindling ammunition supplies.
In an ironic twist, Angel chooses to give his share of gold to Pike, requesting that a crate of rifles be sent to a group of peasant rebels opposing Mapache. The train heist goes mostly according to plan until Thornton’s posse confronts them, leading to a high-stakes chase that takes them to the Mexican border. The gang successfully destroys a trestle bridge to thwart the posse's pursuit, sending the hunters tumbling into the river.
Pike senses a potential betrayal from Mapache and devises a plan to sell the stolen goods in installments. However, Mapache uncovers the truth about Angel's theft of some weapons. In a tragic turn of events, Angel is captured and brutally beaten when Mapache gives Dutch the option to save himself by denouncing Angel.
As tensions rise, Sykes is injured while trying to secure additional horses. Despite Dutch's resentment toward Thornton for his dealings with the railroad, Pike insists that Thornton "gave his word" and must honor it. Dutch, clearly frustrated, retorts, "That ain't what counts, it's who you give it to." After burying most of the gold, the gang returns to Agua Verde only to find the townsfolk reveling in the chaotic aftermath of the weapons sale while Mapache parades Angel like a trophy.
Pike and the others decide to forcibly negotiate Angel's release. Although Mapache initially agrees, he cruelly chooses to slit Angel's throat at the last moment. Fueled by rage, Pike and his gang retaliate, sparking a fierce gunfight that sees their numbers dwindle rapidly, claiming the lives of Pike, Dutch, and several others, alongside many soldiers and Mapache's personnel.
When Thornton arrives on the scene, he discovers Pike lying dead and, finding a loaded revolver on him, realizes that the era of men like them has come to an end. Exhausted and dispirited, Thornton permits the remaining posse members to loot Pike’s gang before staying behind. In a poignant conclusion, Sykes returns with Angel's village elder and a rebellion group, revealing that they have avenged the gang by hunting down the bounty hunters and giving Pike's crew a proper burial. Sykes then offers Thornton a chance to join the revolutionary cause against the Mexican regime, to which Thornton smiles and rides off with them, hinting at a new beginning.
