Watanabe Hiroko's fiancé Itsuki died two years earlier in a mountain climbing accident. While looking through his high school yearbook, Hiroko in a fit of grief decides to write a letter to him using his old school address. Surprisingly she receives a reply, not from the dead Itsuki, but from a woman with the same name whom had known Hiroko's fiancé in school. A relationship develops between the two women as they continue to exchange letters and share memories of the dead Itsuki.