Jake's little sister is about to lose her first tooth. But since it's a dragon tooth, it has mystical powers. The Tooth Fairy's assistant, Dr. Diente, has been biding his time until a dragon tooth came along. Seizing his opportunity, Diente grabs the Tooth Fairy's wand and goes after Haley. But he didn't figure on a mystical shield guarding the Long house, as well as the American Dragon.