Extreme survival series Alive returns with four new real-life stories of human endurance, beginning with a reconstruction of British mountaineers Stephen Ball, Anthony Hollinshead and Nigel Vardy's attempt to climb Mount McKinley in Alaska. A blizzard left the trio stranded, forcing them to send one member of the team down the mountain for help. However, when he was left fighting for his life following a fall, the endurance of all three climbers was pushed to the limit