Takashi lives with his mother. One day, Takashi's childhood friend Nao comes over. His mother worries about her son's poor grades and asks Nao to be Takashi's tutor. Though Nao is a plain and gloomy type, she is the class president type with a strong sense of responsibility, so she agrees and starts teaching Takashi. Diligent Nao studies with Takashi, but one time she finds porn in his room. Nao, who is very interested in sex, says she wants to watch him masturbate…
