Rei Kiriyama (Ryunosuke Kamiki) is 17 years old. He started playing shogi professionally in middle school. His parents and sister died in a car accident when he was young, so he lives alone in Tokyo. Rei Kiriyama encounters three sisters who happen to be his neighbors one day. Akari, Hinata, and Momo Kawamoto are the three sisters. This is his first non-shogi encounter in many years. Rei Kiriyama enjoys eating with the Kawamoto family. Rei Kiriyama's contacts with his neighbors allow him to improve as a shogi player and person.