While out watching a movie with Nanoka, Koshiro bumps into his ex and they end up having dinner together. He initially hopes that they can get intimate afterwards, however she tells him her new boyfriend is visiting her. Frustrated, Koshiro goes home, and he inadvertently knocks over Nanoka's bra while changing. He almost gets caught sniffing it, and he realizes that he is attracted to his own sister, even though he can't come to terms with his feeling.