Based on a game by Princess Soft The protagonist, Junna, has a twin sister named Senna. He is an ordinary student at an elite school. However, in the past, a traffic accident deprived him of his parents and his memory. Junna survived the accident, and although he has been looked after by his relatives, he has lived only with his sister. And present... Life with Senna in the same high school is so pleasant that he can forget the severe past. Because he has been in a world where there is only Senna, his life in this town—including the beginning of a new life, new environments, and meetings—is so refreshing. However, he begins to recall the memories he lost in the accident. Though he enjoys happy and pleasant days, he is tossed by the past, the present, and the future. What is the truth hidden in his memory?