The main character, Hinata Kuroto, is searching for her younger sister, who was supposed to have existed in the past, but no one around her remembers. Kuroto then receives a letter from a beautiful transfer student, Shimotsuki Shirai, saying, ``If you want to know about her sister's whereabouts, come to the library after school.'' When Kuroto goes to the library, he finds a half-naked Shirai waiting there for some reason. "Sex & Dungeon!!" A sex metafantasy drawn by manga artist Gensei Sahara!