Junichirou Kagami was a teenage physics prodigy published in Nature, but after college he abandoned science to live as an otaku shut-in, insisting he suffers from YD, a condition that lets him do only what he wants to do. When his sister Suzune pushes him into a substitute physics post at his old high school, Junichirou turns his obsession with anime, manga, and games into unorthodox methods for reaching his students and solving their problems his own way.