The Arrowhead 135 is notorious for cold and extreme conditions. It has been called one of toughest 50 races on the planet and is a human-powered ultra marathon that takes places in the coldest part of winter in the coldest recorded place in the lower-48 states. Racers are fully self-supported and have only 60 hours to travel 135 miles on a snowmobile trail through the northern Minnesota wilderness by either bike, ski or foot. Challenging terrain, unpredictable weather and sleep deprivation challenge even the most hardy athletes. Follow three racers as they attempt to make it to the finish line: Bonnie Moebeck on bike, John Storkamp on foot and Mark Scotch on skis.