Content Warning: This section includes graphic descriptions of injury and suffering, intense psychological distress, themes of mortality, and existential crisis.

In 1985, British mountaineers Joe Simpson and Simon Yates were in the Cordillera Huayhuash mountain range in the Peruvian Andes. They had set up a base camp at 15,000 feet on a dry riverbed, 28 miles from the nearest village. Their camp was surrounded by the snowy peaks of the Cerro Sarapo, Yeupaja, and Rasac. Having completed training climbs to acclimatize to the conditions, Simpson and Yates planned to attempt the 21,000-foot West face of Siula Grande. The mountain was first climbed in 1936 via the North Ridge. However, no one had ever successfully summited the West face.

Simpson and Yates were accompanied by Richard Hawking, whom they met in Lima. Richard was traveling around South America but was not a mountaineer. During the two-day trek to base camp, he was unwell. Trailing behind, he told Simpson and Yates to go ahead while he rested. He spent the night in a pigsty near a hut occupied by two Peruvian teenage sisters, Gloria and Norma, and their younger siblings. Having joined his companions, he planned to stay in camp while Simpson and Yates climbed.