Koudo Ikusei Senior High School is a leading school with state-of-the-art facilities. The students there have the freedom to wear any hairstyle and bring any personal effects they desire. Koudo Ikusei is like a utopia, but the truth is that only the most superior students receive favorable treatment.
Kiyotaka Ayanokouji 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 Kikyou Kushida, two other students in his class, Kiyotaka's situation begins to change.
(Source: Anime News Network, edited)