Miki accidentally overhears her son arguing on the phone with his girlfriend. Worried about her only son, Miki tries to talk to him, but he refuses to talk. She convinces him that she is worried about his precious son, and it turns out that sex with his girlfriend hadn't gone well. Seeing her son's half-desperate attitude, Miki makes a decision. She decides to offer her body to teach her son about sex. Thus begins her educational sex instruction as a mother, not as a member of the opposite sex. However, her son begins to desire it on a daily basis, and gradually becomes addicted to the sexual pleasures he enjoys with his mother...