On a snowy winter day in Kobe, Japan, Hiroko Watanabe (Miho Nakayama) was once again overwhelmed with grief on the second anniversary of her ex-fiancé Itsuki Fujii's death. Unable to suppress her yearning for her deceased lover, Hiroko Watanabe found the address of "Itsuki Fujii" when she was studying in Otaru City in her middle school yearbook, and followed it to send a love letter that she thought was sent to heaven. Unexpectedly, soon Hiroko Watanabe actually received a reply letter signed by "Itsuki Fujii (Miho Nakayama)". After further understanding, she learned that this Itsuki Fujii was a girl of the same age as her, and was also a classmate of her boyfriend Itsuki Fujii (Takashi Kashiwara) in his youth. In order to learn more about her former lover in middle school, Hiroko Watanabe began to exchange letters with the female Itsuki Fujii. And in her constant recollections, Itsuki Fujii gradually discovered that the Itsuki Fujii who had the same name and surname as her in her youth had hidden a tenderness for her.