進学・就職率ほぼ100％、最先端設備を誇る名門校・興道育星高等学校。Kodo Ikusei Senior High School, a leading prestigious school with state-of-the-art facilities where nearly 100% of students go on to university or find employment. The students there have the freedom to wear any hairstyle and bring any personal effects they desire. Kodo Ikusei is a paradise-like school, but the truth is that only the most superior of students receive favorable treatment. The protagonist Kiyotaka Ayanokoji is a student of D-class, which is where the school dumps its inferior students in order to ridicule them. For a certain reason, Kiyotaka was careless on his entrance examination, and was put in D-class. After meeting Suzune Horikita and Kikyo Kushida, two other students in his class, Kiyotakas situation begins to change.
