Natsuki Sotomura is the toughest girl in school, whose reputation as a fearsome one-woman army has garnered her a small following of both rivals and admirers. When she's not shaking down people for money, she's raiding nearby schools or getting into violent fights. With her signature sneer and venomous tongue, Sotomura isn't afraid to go after anyone, students and teachers alike.

At least, that's who everyone thinks she is. In reality, they are not sneers and insults, but a bad smile and a shy personality! And even though the actually sweet-natured Sotomura is the daughter of a former delinquent, her interests are closer to that of a housewife than a gang boss. Fortunately, fellow student Haruno sees past all the misunderstandings and befriends Sotomura. Together they hope to cure Sotomura of her main issue: her horrendous smile.