A story about the physiology of endurance – when our brains tell our bodies to stop – and the psychology of continuing. A story about preparing mind and body for a 2.4 mile swim, 112 miles cycling, then running a marathon. About the people who share that journey with us: family, coaches, friends, ex-boyfriends, and the people we swim, ride and run alongside. What carries us to the finish line? What’s left at the end of 141 miles of swimming, cycling and running?