Koitaro receives a request from a longtime acquaintance, Mai Momoi. The content is a personal survey of my sister, Ai Momoi. Ai jumped out of the hostel where she lived with Mai and entered a man's apartment. Koitaro begins to get involved with Sara Soju with complicated feelings in her heart, but Sara Soju begins to follow her only love of hers. At that time, Koitaro...