Some parts of the soundtrack, composed by Luis Enríquez Bacalov, are featured in the videogame Red Dead Revolver.
During the Mexican Revolution, a Durango-bound government munitions train is forced to stop due to the presence of a crucified army officer on the tracks. El Chuncho Munoz, a gun runner loyal to the revolutionary leader General Elías, leads his gang in an assault on the train. Lieutenant Alvaro Ferreria attempts to save the officer, but upon being fatally wounded by Chuncho, is forced to order the train to run the officer over and escape the bandits. Bill Tate, an American passenger on the train, kills the engineer and stops the train again, allowing Chuncho and his gang to kill the remaining soldiers and take their weapons. Posing as a former prisoner of the army, Tate joins the gang, and is quickly befriended by Chuncho, who nicknames him "Niño".
After several heists, the gang travels to the town of San Miguel, where Chuncho meets with his old friend Raimundo to overthrow the weakhearted town boss, Don Felipe. Rosaria, Felipe's spirited wife, attempts to defend him; when Chuncho's men assault her, Tate angrily berates them for their behaviour. Chuncho shoots Guapo, a gang member, for attempting to kill Tate. Don Felipe is made to drive Chuncho and his gang back to San Miguel, and he is eventually executed.
Chuncho prepares to stay in San Miguel, drilling the villagers in the hopes of becoming a General himself; Tate convinces much of the gang to leave San Miguel so they can sell their weapons to Elías. Eventually missing his bandit lifestyle, Chuncho leaves San Miguel under the care of El Santo, his priestly half-brother, on the pretext of recovering a gold-plated Hotchkiss M1914 machine gun from his former gang. After killing one of them, Picaro, Chuncho resumes leadership of the others, hoping to sell the weapons to Elías before returning to San Miguel.
Elías' emissary arrives, but is pursued by army troops. Tate and Chuncho use the machine gun to decimate the troops, but at the cost of the lives of nearly all of Chuncho's remaining gang. Unseen by the others, Tate also kills the emissary. Adelita, Chuncho's last surviving loyal gang member, abandons the pair after her lover, Pepito, is killed in the battle. During the ride to Elías' camp, Tate falls victim to a malaria attack. While getting quinine pills for Tate, Chuncho finds a golden bullet among his possessions.
Chuncho and Tate arrive at Elías' camp the next morning, where they encounter several starving revolutionaries. Chuncho sells the guns and is paid five thousand pesos, before learning from Elías that the people of San Miguel were massacred by the army. Realising his irresponsibility, Chuncho allows himself to be executed by Santo, one of the sole survivors of the attack. Meanwhile, Tate, from a high vantage point, shoots Elías and kills Santo before Chuncho's sentence can be carried out. Tate escapes as Elías' doctors pronounce his death: shot in the head with a golden bullet.
Weeks later, Chuncho, now an impoverished beggar, tracks Tate to a hotel in Ciudad Juarez and tries to shoot him. Tate, insisting that he has been waiting for him, gives him a half share of the reward he received from the Mexican Government for assassinating Elías: one hundred thousand pesos in gold. Chuncho, astonished by Tate's apparent loyalty and friendship, visits a barber, a tailor and a brothel.
The next morning, the pair prepare to leave for a new life in the United States. However, when Chuncho watches as Tate cuts through a line of Mexicans to buy their train tickets, he begins to reconsider their relationship and his responsibilities. Learning that he had been further manipulated by Tate through his pretending to be an army prisoner, Chuncho suddenly declares that although they are friends, he must kill him. Tate asks why, to which Chuncho replies "¿Quién sabe?" before shooting him. Tate's body begins its return to the United States, while Chuncho, laughing manically, flees from the authorities down a corridor of carriages, exhorting the poor to buy dynamite instead of bread.
Damiano's film has been called a "serious statement about the Mexican Revolution" and has been recognised as an accomplished blend of "tension, action, politics and history".