Billed as ‘The Last Great Race on Earth’, the Iditarod Trail is the toughest dog sled race in the world. Snaking through over a thousand miles of the Arctic’s harshest wilderness, the race is one of Alaska’s proudest traditions and Lance Mackey is its greatest champion. He’s a man with dog sled racing hard wired into his family, across generations. And he’s a man who has battled homelessness, addiction and cancer, but who has always returned to the sled.