[1] The protagonist is based on the real-life "Joe Rivers," the pseudonym of a Mexican revolutionary whose boxing winnings supported the Junta Revolucionaria Mexicana, a group of revolutionaries-in-exile.
[2] The story centers around Juan Fernandez, the son of a Mexican printer who had published articles favorable to striking workers in the hydraulic-power plants of Río Blanco, Veracruz.
Adopting the new name of Felipe Rivera, he volunteers to serve the cause at the office of the Junta, whose personnel suspect his motives and put him to work doing menial labor.
Rivera surprises his colleagues by occasionally disappearing for days or weeks at a time, then returning with much-needed funds and displaying fresh injuries apparently caused by fighting.
Ward's scheduled opponent has broken his arm and is unable to fight; Rivera offers to take his place, insisting on a winner-take-all contract once he learns that the prize money will be more than enough to afford the guns.