Madoka, a housewife living a peaceful life with her son and husband, has raised her son to be a serious and honest man thanks to her strict education. On the other hand, Madoka is a sexually active mother and cannot be satisfied with just her husband's sex life, so she spends her days masturbating whenever she gets the chance. One day, her son accidentally witnesses her in the act. Tormented by his feelings, he causes a problem at school by forcing sexual acts on a female student. Madoka blames herself for her son's problem and decides to give him sex education, thinking, 'I have to teach him myself...'.