Conrad Anker is one of the greatest and most notorious professional mountain climbers in history. But at 54, his career in the big mountains is winding down, especially after suffering a heart attack on a climb high in the Himalayas. His friend Alex Wildman is a novice big-wall climber and cardiac nurse who recently recovered from stage 4 lymphoma and intense chemotherapy. With a new lease on life, Alex is hungry to return to a life in the mountains. Together, they team up to support each other on a climb up Yosemite's El Capitan, and put their traumatic brushes with mortality behind them.