At the prestigious Kōdo Ikusei Senior High School, nearly all graduates advance to university or secure employment with remarkable ease. The campus boasts state-of-the-art facilities and grants students complete freedom over personal appearance and belongings, presenting an image of academic paradise. Behind this polished facade, however, lies an unforgiving truth: only superior students receive genuine institutional advantages, while others endure systematic neglect and ridicule. Kiyotaka Ayanokōji occupies D-class, the lowest academic tier where the school deliberately isolates struggling students. Rather than happenstance, his placement stems from calculation—Kiyotaka deliberately underperformed his entrance examination to land unnoticed in this overlooked division. His carefully balanced circumstances shatter upon meeting Suzune Horikita and Kikyō Kushida, both D-class students whose arrival sets in motion a chain of developments that threatens to expose everything he's worked to conceal.