Exhausted and nearly drowned, Jack washes up on a mysterious island after a murderous storm. Desperate for rescue, he searches the beaches and meadow for someone who can help him. He finds sheep dogs herding sheep, and fearsome wild dogs lurking in ambush, but strangely, no people.

Soon Jack is struggling to survive in the wild, using his wits and some tools he finds in the ruins of old dwellings, He tries hard to understand the sheep dogs and fight off his loneliness, and eventually befriends a little Border collie named Moxie. But she and the other sheep dogs remain mystified by the skinny boy who does not fit their myths about people.

During a fierce battle between the sheep dogs and their terrifying wild forest cousins, Jack faces his fears and decides to join the noble sheep dogs in their fight. Suddenly he is no longer a shipwrecked orphan -- Jack belongs now with the dogs, and is willing to forget the human world forever.