The housemaid Micchan tells Migi and Dali that the Ichijo family has a room with water flea wallpaper. They begin attending school to befriend Eiji, the son of the Ichijo family. However, to get close to Eiji, they need to score well on tests and join a top class. The two start studying diligently to boost their grades, but unexpectedly, Migi falls head over heels for a certain female student in the library.