The Legend of Dragon Tooth" is the fourth episode of season one and the sixth episode overall.
Jake's little sister was about to lose her first tooth. But since it was a dragon tooth, it had mystical powers. The Tooth Fairy's assistant, Dr. Diente, had been biding his time until a dragon tooth came along. Seizing his opportunity, Diente captured the Tooth Fairy, grabbed her wand, and went after Haley. However, he did not figure on a mystical shield guarding the Long's house, as well as the American Dragon.
Meanwhile, Jake wanted to go to a concert. However, while he was getting ready, his mother came in and told him him that he had to babysit Haley, so now he couldn't go to the concert. Thanks to Spud and Trixie's arrival and assistance, Jake got to attend the concert. Spud and Trixie took care of Haley for 20 minutes, and then Jake came back and babysat Haley for another 20 minutes.
Eventually, when Jake's idol singer was on TV, Trixie and Spud could not babysit Haley because they wanted to watch as well. So now Jake took his sister to the concert, but the evil dentist kidnapped Haley and took her to the Tooth Fairy's lair. Haley lost her dragon tooth, and Diente now had it and started possessing magical powers. However, Jake grabbed a billboard-sized TV screen and smashed it on top of the dentist, defeating him. Jake then took Haley home and put her to bed, and Haley thanked Jake for missing the concert to save her.