20-year-old Nana Yasuda hasn't visited a dentist since her ○○ school days—about 10 years ago. Suffering from extreme dental phobia, she finally returns for treatment after being unable to endure the pain of tooth decay any longer. A decade of neglect has left her teeth in a severe, lawless state. This time, the fifth lower left tooth requires treatment, as the previously applied sealant has come off, allowing decay to progress and form a cavity. The procedure begins with drilling, but shockingly, no anesthesia is administered, causing Nana to become even more terrified. Overwhelmed by the intense pain, she decides to flee before the inlay can be placed, cutting off all contact. Her appointments are canceled, plunging the situation into crisis. Despite the risk of further decay from continued neglect, what will become of Nana's fate?