War rages between two neighboring countries, but one side has an ace up their sleeve: an ancient dragon bound by a pact to protect the nation. Despite these overpowering creatures being capable of leveling entire battlefields, they are rendered useless by cavities. And so, a special unit—the dragon dentists—has the important duty of caring for the dragon's teeth.

Nonoko Kishii was the only one of many brave volunteers who survived a recent round of recruitment; in order to join the dragon dentists, one has to witness their future demise and accept it without a fight. Knowing the exact circumstances of their fated ends, the dragon dentists devote themselves to their work. One day, they gain a new member who did not undergo the test: Bernard "Bel" Octavius, a young enemy officer killed by his own men and revived by the dragon's teeth. Despite his appearance being an omen of a great disaster, he is placed under the care of Nonoko as a dentist-in-training. Will Bel come around to the dragon dentists' attitudes toward death and help them face the painful future that is to come?