Sled dogs must love to run. Sled dogs must be strong. Sled dogs must obey commands. Sled dogs must get along with teammates. Puppy Yukon is the only girl in her litter, and she's got high energy. Could she be a leader in the sled dog team? Trainer Roberta works with the puppies. Yukon is faster and smarter than her brothers. Roberta thinks Yukon can help lead the team! Yukon continues to train with her team for two long years. Is she finally ready to race? Mush! Mush!