During the Mexican Revolution, a peasant named El Vasco starts a revolt in his town of San Bernardino by killing the army colonel in charge.

Xantos is the leader of a student counter-revolution that opposes violence, and is held in a prison by the United States army just across the border in Yuma, after he tried to find funding from the US and did not agree to give the monopoly of his country's entire oil wealth in return.

El Vasco dislikes the suit-wearing Peterson and calls him a "penguin", but at the suggestion of General Mongo, the two reluctantly join forces and set out to capture Xantos.

In order to maximize their personal gain and to support Xantos' rebel fighters, El Vasco and Peterson have to doublecross Mongo.

El Vasco and Peterson team up with Lola and the surviving Xantistas to launch a climactic attack on San Bernardino.

When news arrives that a large Federale counter-revolutionary army is marching onto San Bernardino, Peterson decides to leave aware that the Xantistas are outnumbered and outgunned, but El Vasco urges him to stay and fight.