Mio is a single mother raising her two sons. The elder brother, Kota, is a responsible working adult, but the younger brother, Eiji, makes a reckless decision to drop out of college and become a host. To correct Eiji's misguided path, Mio decides to use her strong sexual allure to seduce him. As a result, both brothers fall into forbidden erotic temptation, giving rise to a new and taboo relationship.