Musher is a film about the lives of four sled dog racers (mushers) and their dogs. What it means to be a musher, and what it takes to be a sled dog, is revealed over the course of a year as they all wait out summer so they can train for the coming winter's races. The film also explores the role of women in the sport, as dog mushing is one of just a few sports where men and women compete together.