Kono Yo no Hate de Koi o Utau Shoujo Yu-no

Takuya Arima is a third-year student at Sakaimachi High School whose father, a researcher, recently disappeared in an accident. As summer vacation approaches, Takuya receives a package from his father containing a mysterious relic called the Reflection Device. Following the instructions noted in his father's letter, he finds himself on the islet of Ken no Misaki and meets a strange young woman who mistakes him for a certain "Yu-no." She disappears immediately after kissing him. As circumstances unfold, Takuya will travel through various parallel worlds in order to discover the truth behind his parents' strange disappearance.