In 1985, Simon Yates and Joe Simpson attempted to be the first to successfully ascent the West Face of the 6,244 metre tall Siula Grande, located in the Peruvian Andes, taking an inexperienced Richard Hawking to stay at 'base camp'.
Having successfully ascended the West Face of the Siula Grande (despite set-backs due to weather), using the 'Alpine' climbing method, Yates and Simpson turned their minds to descending the challenging North Ridge. It was at this point when the attempt started to go from difficult to disastrous, as Simpson slipped on an ice cliff, falling and landing in a way that crushed his tibia (shin-bone) into his knee joint, thus warranting his right leg broken.
With Simpsons' broken leg, and no gas left to melt snow/ice for drinking water, the pair knew they would have to descend the remaining 1,000 metres as quickly as possible if they were to survive. After much deliberation, the pair decided the best way to descend would be for Yates to join two 150 foot ropes together and slowly lower Simpson. Because of the ropes' joining knot, Simpson would have to place his weight onto his good left leg every 150 feet. With visibility dwindling due to stormy conditions and night time approaching, Yates accidentally lowered Simpson off the edge of a cliff.
Because of his position in relation to Simpson, Yates could not hear or see him. Simpson decided to attempt to climb up the rope using a Prusik knot, but this went from difficult to near-impossible when he dropped one of the cords needed to ascend the rope. Simpson was left hanging off the cliff for a long time.
This was a very bad scenario, as not only was Simpson unable to climb the rope, but Yates was stuck on soft snow which was likely to give way, most likely pulling them both to their deaths. Yates made the tough decision to cut the rope to save himself from being dragged to his death. Simpson then plummeted into a deep crevasse, of which there seemed to be no escape. Yates, suffering from exhaustion and hypothermia, dug himself a 'snow cave' to shelter from the storm.
The day after, Yates continued to descend the mountain reaching the crevasse. After shouting Simpson with no reply, Yates came to the conclusion that Simpson was dead. Yates successfully reached base camp again, telling Hawking about what had happened. Simpson, however, had survived the 150 foot drop - landing on a small ledge just a few feet away from another drop deeper into the crevasse. Simpson realised it was impossible to climb back up to the crevasse entrance (because of overhanging ice and his broken leg). After going through a period of strong anxiety, stress, and depression, Simpson decided his only option was to use the rope Yates cut to descend further into the crevasse.
After descending, Simpson noticed a second small entrance to the crevasse, of which a steep slope of snow led up to. Simpson managed to pull himself up this ledge, after crossing an unstable ledge of hollow ice. From this point, Simpson went three days without food or drinking water, crawling and hopping the remaining five miles back to base camp. This meant navigating through a glacier littered with more crevasses, similar to the one that Simpson was stuck in. Simpson was exhausted and very delirious, and at one point Boney M.'s song "Brown Girl in the Ring" was looping through his head.
Only hours before Yates and Hawking were to return back to society, Hawking was awoken by the distant sound of Simpson shouting "Simon!" and went to investigate. This is where Joe Simpson was found, crawling helplessly towards base camp. Yates and Hawking carry Simpson back to the camp, where they try to rebuild some of his strength.