Yuri's sister Misaki passed away. While attending her funeral, she met her niece, Misaki's daughter Ayumi who informed her there was a letter left to Ayumi. Yuri went to the school reunion to inform people of her sister's death but due to a misunderstanding, she was mistaken as her sister Misaki. At the reunion, she met her first love Kyoshiro. Continuing the misunderstanding, she starts to exchange letters with him pretending to be MIsaki. When she received a letter addressed to Misaki, memories of her youth with Misaki and Kyoshiro came back.