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.
Still mournful over finding out Rose is the Huntsgirl, and thus being forced to shun her affections, Jake is kidnapped by The Huntsclan along with other magical creatures as part of their "Grand Equinox Hunt," where they are set free to be hunted down by the Huntsclan. When he doesn't drop subtle hints at Rose about the true nature of their relationship, he realizes that as a dragon, he must help a water-fearing mermaid, a hot-blooded brownie, a giantess, and an unlucky Leprechaun to defend themselves in the hunt.