Pinned down in deep snow and running out of food, veteran thru-hiker Stephen “Otter” Olshansky scraped his way to a campground latrine, holed up inside, and prayed for help to arrive.

He was the best alpinist of his generation, a quiet, unassuming Canadian known for bold ascents of some of the world’s most iconic peaks. Four months ago, at the age of 25, he traveled to Alaska to join climber Ryan Johnson for a first ascent outside Juneau. They never came back.