Kouta, who has been dating his girlfriend Yoshie for three years, has recently had a problem. It was that he had grown tired of her during the period of boredom, and that he had begun to take an interest in her mother's beauty. Knowing or ignoring Kota's feelings, his mother unexpectedly confesses, "I've fallen in love with you." Kouta is puzzled by the sudden turn of events, but he sleeps with his mother even though he knows that he is betraying Yoshie.
