In 1937, Mount Lucania was the highest unclimbed peak in North America. Located deep within the Saint Elias mountain range, which straddles the border of Alaska and the Yukon, and surrounded by glacial peaks, Lucania was all but inaccessible. The leader of one failed expedition deemed it impregnable. But in that year, a pair of daring young climbers would attempt a first ascent, not knowing that their quest would turn into a perilous struggle for...