“Who am I really?” Due to a traffic accident 18-year-old heroine, Yuki Hinata lost her memory. To her who lives well without taking care of that. One day, a strange event begins to fall. A strange diary was placed in a room that doesn't belong to her... A strange handsome guy who suddenly talks to her... And an abnormal constitution that always falls asleep "at a fixed time" ... The mystery deepens and love is born.