Masanobu is a quiet and withdrawn high school student who has recently raised the concern of his mother, Momoko, as he has been returning home from school covered in bruises. Momoko believes that her son is being bullied; Togawa, one of Masanobu's classmates, confirms her suspicions.


Togawa reveals that Masanobu is frequently bullied at school, but also uses the opportunity to bring up a problem of his own: he is belittled at school because he is a virgin. As her husband is away, Momoko sympathizes and casually offers Togawa a chance to play with her breasts.


However, as this innocent foreplay quickly escalates to regular intercourse, Togawa's devious ulterior motives are slowly revealed.