Seventeen-year-old Rei Kiriyama is a professional player of shogi, or Japanese chess, who has been lionized as a genius but was orphaned at age nine and has no family or friends. One day, Akari Kawamoto helps him out when she finds him sick and collapsed in the street. From that day onward, he gets to know the eldest daughter Akari, middle daughter Hinata, youngest daughter Momo and their grandfather Someji.