 Hiroko Watanabe 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 her dead husband, but from a woman also named Itsuki whom had known Hiroko s husband in school. A relationship develops between the two women as they continue to exchange letters and share memories of the dead Itsuke.