Nonoko is a newly appointed dentist who protects the dragon, the guardian of the country, from tooth cavity bacteria. One day, amid increasingly fierce battles against the neighbouring country, she finds an unconscious enemy boy soldier on the dragon's tooth. His name is Bell, and he has been "resurrected" from within the tooth by the dragon, a supernatural phenomenon that legend says occurs before a major disaster. As Bell also becomes a dragon dentist, an unexpected and tremendous explosion gives rise to countless tooth decaying bacteria.