On New Year's Eve, a twenty-something year old Hamaji returns home and finds his old classmate Sakura Momoko's diary hidden under the shoe cabinet in his home. Fifteen years had passed since Gr.3 Cl.4 (in which time Hamaji and all his 3-4 classmates had done a whole lot of growing up). Still curious to know what goes on in Maruko's mind, he flips open the diary and begins to read…

Matt travels to a world where a person's deepest wishes are granted. Here he visits Yuko, a girl he fell in love with in 1999, a girl with a mysterious past, who died protecting her best friend. As Christmas draws nearer so does the time to say goodbye to first love. Slowly Matt begins to reveal why he's writing about Yuko and what he learns about sacrifice and the sibling bond...