The year is 1912, and the Mexican Revolutionaries are fighting battles on many fronts - including the moral; caught in this crossfire is American pilot and adventurer Lee Arnold (Robert Mitchum) - who, in true capitalist spirit, sees no harm in supplying arms and ammunition to counter-revolutionaries like Capt. Francisco Ramirez, smuggling the contraband across the border from Texas, in his WWI pursuit plane, he is paid in gold for his aid. On one such mission, as he is awaiting the repair of the landing gear of his plane, Lee is witness to the violent attack and razing of a village by the Captain and his men (because the villagers curried favor with the insurrectionist Pancho Villa).
Yul Brynner assays the role of Villa; his famous bald pate is given a miss in the film as he sports a toupee and moustache. As in real life, Villa assists General Huerta (Herbert Lom), and has a brutal sidekick in the form of Lt. Rodolfo Fierro (Charles Bronson). Ramirez and his men are defeated by Villa, and even Lee Arnold is taken captive by Fierro - who longs for nothing more than to kill him. He is sentenced for gun-running, to face a firing squad. In order to save his skin, Lee strikes a deal to aid the insurrectionists in their revolution - he would provide them with the guns, instead, fighting on their side. On one such revolutionary escapade, Lee provides air cover to the guerillas as they capture an enemy train carrying troops, and eventually as they make captive an entire town.
There are cracks in every revolution - General Huerta deeply dislikes Villa, believing him to be manipulative and success-seeking. He is furious when Villa captures the town despite the General’s orders not to - causing heavy casualties. Soon after, Huerta plots to send Villa on a doomed mission to capture Conejos, in a bid to ensure he is not around when the General overthrows the government and President Madero - however, Arnold’s aerial assistance saves the day, even though Villa loses many men. And to the General's delight - Villa is captured by him, and Lee crosses the border into El Paso, saving his skin in time!
Now clear about his boss’s intentions, Pancho escapes imprisonment and hunts down Lee, on whose support he has come to rely deeply. A reluctant Arnold agrees to help Villa once more - the Revolutionaries have a new cause: to do away with Huerta, now a self styled dictator after he has assassinated the Mexican president and seized power. Later Arnold also helps Villa raise an army against another enemy of the Mexican state - Emiliano Zapata.
Criticized for its cosmetic portrayal of the Revolution and for not really exploring the many perspectives there exist with regard to it, the film may at least be applauded for its precise portrayal of Villa, who was less a hero and more a man on the run, a hardened criminal known for his thirst for violence.