At ABC, more than 600 climbers prepare for summit attempts. All the climbers on Russell Brice's expedition must prove they're strong enough to climb from ABC to the North Col in less than five hours or he will not allow them to continue. Russell spots a period of light winds in two weeks' time that looks ideal for an early summit attempt. To make this window, however, he'll have to push both his Sherpas and climbers extra hard to be ready two weeks early.