Naho Takamiya sets off on another year of high school when she discovers a strange package in her mailbox supposedly containing letters from herself at 26. Hard to believe at first, her skepticism quickly diminished as the events detailed in the letters begin to unfold. The focus of the correspondence to herself is centered on a student named Kakeru Naruse who appears to not be with her in the future. Guided by her future-self, will she and her friends be able to help Kakeru before it’s too late?

After facing horrific loss in his life as a child, Rei Kiriyama is adopted, trained, and quickly excels at the sport of shogi, so much so that he became a professional shogi player when he reached middle school. Now, a few years after becoming a professional, the pressure placed on him to succeed and face his demons become almost all-consuming if not for the kind support of mentors at the shogi hall as well as Hinata, Akari, and Momo Kawamotio, three neighbourly sisters.