The story centers around Felipe Rivera, the son of a Mexican printer who had published articles favorable to striking workers in the hydraulic power plants of Río Blanco, Veracruz. The workers are locked out, and the federal troops are sent against them. Rivera escapes the massacre by climbing over the bodies of the deceased—including those of his mother and father. He makes his way to El Paso, Texas where he comes into contact with the Junta Revolucionaria Mexicana. He volunteers to serve the Revolution at the office of the Junta, who, suspicious, put him to work doing menial labor.
Soon, however, he is dispatched to Baja California to reestablish connections between Los Angeles revolutionaries and the peninsula. Exceeding his orders, he assassinates federal General Juan Alvarado and returns to El Paso.
The fate of the Revolution hangs in the balance as the Junta scrambles to finance the revolutionary armies. Rivera, who has been boxing on the local circuit to support the Junta, decides to fight the well-known boxer Danny Ward in order to secure the funds needed by the Junta. He negotiates a winner-take-all contract for the fight, on Ward's condition that the weigh-in occur at ten in the morning rather than immediately prior to the fight.
The fight lasts seventeen rounds, but eventually Ward succumbs to Rivera, who is fueled by visions of violent vengeance.