

Film ini menceritakan kisah romantis yang berpusat pada karakter dari dua generasi, dimana ceritanya bermula pada saat surat yang salah kirim. Yuri Kishibe, yang pergi ke reuni kelas adiknya Misaki Tōno untuk memberi tahu mantan teman sekolah tentang kepergian adiknya. Di sana, ia bertemu cinta pertamanya, novelis Kyōshirō Otosaka. Keduanya mulai menulis surat satu sama lain. Fukuyama memainkan Otosaka versi dewasa, sementara Kamiki memainkan Otosaka pada saat SMA.
It is only at their sister’s and mother’s funeral when a woman meets her niece after many years. The niece is now a grown girl. The sister takes on the task of informing the deceased’s friends of the death while the daughter cannot bring herself to symbolically accept the demise of her mother. In the midst of all this an old flame messages the sister to say he is still in love with her, but is he messaging the living sister or the dead one?