Akihisa's sister, Akira, comes to his house to check up on him, and checking to see if there are evidences of any girl in his life besides her, much to his angst. Things go from bad to worse for him when his friends suspect him of hiding something, and Mizuki, who now was acting strange after Kouta stated that he might have a girlfriend, wants to enter his room. Then as they reach the door, a surprise awaits them which can test both Mizuki and Minami's denial...
明久的姐姐玲原本住在國外，沒想到某天突然回到日本，而且還是穿著浴袍。玲說她是來檢查明久的生活狀況，並將根據下次考試的結果決定是否讓明久繼續一個人住。隔天，明久的生活態度完全改變。雄二等人對明久這種不自然到極點的改變感到可疑，但明久仍拚命想隱瞞理由……？
La sorella di Akihisa, Akira, torna a casa per controllarlo e per decidere se può continuare a vivere da solo. Le cose peggiorano ancora di più, quando gli amici di Akihisa si autoinvitano a casa sua.
