One of the toughest competitions in the world is back for round three as 12 of the world's toughest outdoorsmen face off against each other, Mother Nature, and their own will to survive. This fight to the finish isn't about money or a prize; it's about pushing the limits of human endurance. It's a dangerous test of strength and determination. And in the end, only one team will be crowned the winner. Four teams—Military, Endurance, Alaskans, and this season's new team, Lower 48—face peaks, deadly tidal waves, massive glaciers, bottomless crevasses, man-eating predators and treacherous white water. In each of the 13 legs this season, teams have just 60 hours to make it from start to finish … surviving off the land with only the gear on their backs. No GPS. No phones. No mercy.