The film follows the journey of Argentine revolutionary Ernesto "Che" Guevara from his initial involvement with the Cuban Revolution to his rise as a pivotal figure in the movement. It begins with Guevara's initial meetings with Fidel Castro in Mexico City, where they plan the overthrow of Cuban dictator Fulgencio Batista. Guevara, a physician turned soldier, joins Castro’s group of 82 rebels as they sail to Cuba on the yacht Granma. Once in Cuba, the group is met with hostility and treachery but slowly gains support from the rural campesinos, who are persuaded by their message of agrarian reform and social equality. The narrative captures their guerrilla warfare tactics and the arduous battles in the mountains and jungles of Cuba as they gather strength and followers.

As the revolution intensifies, Guevara emerges as a charismatic and strategic leader, whose medical background and dedication to education earn him the respect of his comrades and local peasants alike. The film intersperses scenes of Che at the United Nations in 1964, where he passionately speaks about the injustices faced by oppressed people around the world. Through a juxtaposition of these diplomatic moments with flashbacks to the guerrilla warfare in Cuba, the film provides a multifaceted portrait of Guevara, not just as a revolutionary but also as a global icon for change. The story illustrates the incremental victories that lead toward their ultimate goal of inciting a successful revolution.