Fuutarou Uesugi is a poor, antisocial ace student who one day meets the rich transfer student Itsuki Nakano. They argue but when Uesugi realizes he is to be her tutor, he tries to get on better terms. While trying to do so he meets four other girls.
Futaro already has his hands full with the quintuplets, but when his first love shows up out of nowhere, things get even more complicated. From costumes to competition, how each of the sisters tries to win him over may just seal their fate—and his!