Kagami Jun'ichirou's sister Suzune is angry at him because of his complete disinterest in the real world. As he is interested in nothing but anime, manga and games, Suzune forces him to get a job as a physics teacher substitute at the same high school from which he graduated. Jun'ichirou proves himself a capable and hard-working teacher who comes up with unorthodox methods based on the seemingly useless knowledge he obtained as an otaku to teach and motivate his students. Source: Wikipedia