Chika is a housewife who is dissatisfied with her husband, whose libido has been declining. Even though it's been a while since they last had sex, he only uses toys and his penetration ends quickly, which has left her feeling frustrated. One day, Chika notices that her son's crotch is erect while he is sleeping, and it has been bothering her ever since. She tries to satisfy her lust by masturbating, but it just doesn't go away. Finally, feeling that she has reached her limit, Chika takes off her sleeping son's pants and reaches for his hard, erect cock...