The film opens with a poignant series of photographs showcasing the Stella Maris College's Old Christians Rugby Team. Carlitos Páez narrates the story, explaining that the images were captured by his father. He points out various members of the team, including himself as a youth, Alex Morales, Felipe Restano, Nando Parrado, and their captain Antonio Balbi. In a reflective monologue, Carlitos speaks on themes of heroism, the seriousness of their predicament, as well as solitude and faith.
The narrative transitions to October 13, 1972, where Uruguayan Air Force Flight 571 embarks over the majestic Andes. The atmosphere is filled with excitement as the rugby players and their friends anticipate the upcoming match in Chile. Nando's sister, Susana, expresses her admiration for the scenic mountains, noting they'll land in just 20 minutes. Unfortunately, their thrill is abruptly halted as the plane emerges from a cloud cover and is met with turbulence, tragically colliding with an unseen mountain peak. The impact tears the wing and tail from the aircraft, sending the remains crashing down the slope until they finally stop. Antonio Balbi, demonstrating leadership, takes charge, guiding his injured teammates in a desperate attempt to cope with the chaos. Medical students Roberto Canessa and Gustavo Zerbino rush to tend to the injured, but the heavy toll of the crash claims six lives instantly, including the steward, with another six succumbing to their injuries shortly thereafter – among them Alex, Nando's mother Eugenia, and an elderly couple. Despite sustaining a head injury, Nando falls into a coma, rendering Susana in a dire condition.
As night descends, the survivors scramble to prepare for a frigid night. To stave off the cold, Canessa finds a way to unzip the seat covers and use them as makeshift blankets. They huddle within the fuselage, attempting to shield themselves from the chilling winds by plugging a gaping hole with luggage. Tragically, two passengers perish that night from their injuries, including Mrs. Alfonsín, casting a shadow over Carlitos, who regrets having raised his voice at her earlier.
With scarce resources on the mountain, Antonio decides rationing is essential after they stumble upon a tin of chocolates and a case of wine. They momentarily cheer when a plane dips its wing above them, fostering hope for rescue, though only Javier, his wife Liliana, and Antonio indulge in the chocolate, believing they'll be saved by the next day. Their hopes are shattered after hearing via radio that the search efforts have been suspended on the ninth day, igniting a heated argument among the survivors about the rationing of chocolates. In the meantime, Nando awakens thanks to the care of Carlitos and Hugo Diaz. After the anguish of learning about his mother’s demise, he becomes vigilant over Susana, who, unfortunately, only has days remaining due to her injuries.
Desperation leads Nando to suggest consuming the flesh of the deceased pilot for sustenance, a decision borne from necessity when faced with starvation. With heavy hearts, the survivors collectively agree to resort to cannibalism for survival. Zerbino, Rafael, and Juan Martino embark on a quest for the plane's tail, hopeful to retrieve the batteries of the radio for a signal, but return empty-handed. Their search brings additional grim discoveries among the wreckage, yet they learn the tail may lie just beyond their sight. A few days later, an avalanche engulfs the wreck, burying many beneath layers of snow; amongst the casualties are Antonio, Liliana, and Juan, marking a tragic blow to the remaining survivors as Liliana becomes the last of the five women aboard to perish.
Nando's group, containing Canessa and Antonio "Tintin" Vizintin, eventually locates the plane's tail. Despite their efforts, an unsuccessful attempt to repair the radio with Roy's help leads them back to their makeshift shelter. Soon after, additional casualties mount as Federico Aranda and Alberto Antuna succumb to their injuries, leaving Nando to persuade a hesitant Canessa to search for an escape route from the mountains – taking "Tintin" with them. After sending "Tintin" back to conserve food supplies, the duo embarks on a rigorous 12-day trek, finally reaching safety and alerting authorities to their companions’ plight. Joy fills the air as helicopters arrive to rescue the remaining 14 survivors.
The film concludes as Carlitos reflects on the survivors' return to the crash site, where they respectfully buried their deceased companions under rocks, commemorated by a cross placed half a mile away, beautifully honoring both the 29 lost souls and the 16 survivors.
