Chiharu eavesdrops on her son and his best friend Kazuya having a lively conversation about virginity. Kazuya is still a pure adolescent boy who doesn't know the pleasure of sex and is curious about it, and Chiharu's daily frustrations and maternal instincts are on the verge of exploding. When Kazuya comes over while her son is out, she invites him into her house and begins to teach him about sex, saying, "Are you interested in a woman's body? If you want, I'll teach you..."