Jack, a storm-snatched cabin boy, washes up on a mysterious island. He finds sheep, sheep dogs, and wild dogs called fangos, but strangely, no people. Jack struggles to survive, to understand the dogs, and to befriend a little Border collie named Moxie. She and the other sheep dogs are mystified by the skinny boy, who does not fit their myths about people. During a final battle between the fangos and the sheep dogs, Jack finds he can communicate with the dogs, a discovery that deepens his friendship with Moxie and validates his life on the island. But the crew from Jack's ship returns to rescue him-now that Jack does not want to be rescued.

This middle-grade novel, told from Moxie's and Jack's alternating points of view, reads like a classic adventure story-vivid, swiftly paced, and woven with the timeless themes of a boy's self-reliance and the intense loyalty of dogs.