In 1985, two young climbers, Joe Simpson (Brendan Mackey) and Simon Yates (Nicholas Aaron), set out to be the first to reach the summit of the Siula Grande in the Peruvian Andes. They succeed, and the two embark on the treacherous descent down the mountain — only to meet with disaster when Simpson breaks his leg in a fall, leaving Yates to lower him the rest of the way with ropes. When a storm threatens both their lives, Yates must decide whether to cut the rope and risk Simpson’s likely death.