"Hiroko attends the memorial service of her fiancé, Itsuki Fujii, who died in a mountain-climbing incident. Although Itsuki's mother says that their old house is gone, Hiroko records the address listed under his name in his yearbook and sends him a letter. Surprisingly, she receives a reply, and discovers it came from his old classmate, a girl who also happens to also be called Itsuki Fujii."