In 1952, just a semester away from earning his medical degree, Ernesto "Fuser" Guevara sets off on an adventurous journey with his older companion Alberto Granado, a biochemist, as they leave Buenos Aires for an extensive trek across South America. Although they have a noble goal of working in a leper colony in Peru, what initially drives them is the thrill of exploration and joy. Over the course of four and a half months, they plan to traverse more than 14,000 kilometers (8,700 miles), all the while Granado's intentions include charming as many women as he can along the way. Their adventure kicks off with Granado's unreliable motorcycle, affectionately named La Poderosa, which means "The Mighty One."
Their ambitious itinerary leads them north over the Andes, down the Chilean coast, through the scorching Atacama Desert, and into the lush Peruvian Amazon, aiming to reach Venezuela in time to celebrate Granado's 30th birthday on April 2nd. However, due to mechanical failures with La Poderosa, they frequently find themselves walking and traveling at a much slower pace, delaying their arrival in Caracas until July.
As the journey unfolds, both Guevara and Granado gain profound insights into the stark realities faced by the indigenous population, revealing the painful discrepancies between the affluent "haves," which they represent, and the oppressed "have-nots." A poignant episode in Chile exposes them to a destitute couple cast out due to their communist ideals. In a revealing moment, they confide in the couple that they are not in search of work either, which leads them to visit the Chuquicamata copper mine, where Guevara's indignation boils over at the mistreatment of the workers.
The transformative experience continues at the breathtaking Machu Picchu in Peru, where Guevara reflects on how a once-thriving indigenous civilization capable of such magnificent achievements was ultimately eradicated by the very forces contributing to the urban decay of polluted Lima.
In another striking episode, they dedicate three weeks at the San Pablo leper colony in Peru. Here, Guevara profoundly observes the societal divide: medical staff live on the north side of a river, untouched by the lepers confined to the southern shore. In a brave act of solidarity, Guevara defies the head nun's directive to wear rubber gloves, opting instead to shake hands with the leper patients, challenging the misconceptions surrounding leprosy.
As the film approaches its climax, Guevara's awakening thoughts culminate in a heartfelt birthday toast—his inaugural political speech—where he passionately advocates for the unification of South America, emphasizing the need for solidarity among the Mestizo populace. The journey fundamentally alters Guevara's worldview, instilling seeds of revolutionary thought that would lead him down the path of Marxist activism.
In a symbolic night passage, despite the danger and his struggle with asthma, Guevara swims across the river, opting to spend the night in a leper hut rather than the doctors' quarters. The poignant journey culminates at an airport, where Granado admits that his birthday is actually on August 8th and that their supposed goal was merely a motivator for the trip. Guevara, having been aware of this all along, shares a knowing glance. The film concludes with the special appearance of the real Alberto Granado, now 82 years old, showcasing photographs from their journey and briefly mentioning Che Guevara's eventual assassination by the CIA in Bolivia in 1967.
