In the Colorado mountain town of Steamboat Springs there must be 300 dogs. Jack's malamute, McKinley, is the leader of them all. But Jack, being human, has no way of knowing that. For him, his family's dog is just a great pal — and protector. Jack doesn't realize that Redburn, an Irish setter, is McKinley's rival for the job of head dog. The boy cannot know, with the sudden hillside appearance of a she-wolf, Lupin, that not only McKinley's job — but his life — is in danger.