27-year-old Sakumi Shimura lost the last 10 years of her memory from a car accident. Sakumi can only remember events up to when she was 17-years-old, but she accepts her fate and tries to stay positive. Nevertheless, Sakumi is bothered by the loss of her memory. She tries to remember with the help of Yoshihiko, who thinks of himself as her boyfriend and her friend from their high school days.