Team One is the first to head into the death zone, where the extreme altitude shuts down digestion and the body starts to consume its own muscle tissue for energy.After only a few hours at the top camp, Team One leaves in the darkness at 1 a.m. for the summit. Almost immediately, they are caught in a frustrating human traffic jam that stops them in their tracks. If they can't pass some of the slow climbers on the ropes ahead of them, they could run out of time…and oxygen.