Yaichi Kuzuryu is a teenage shogi prodigy who holds the Ryuo, the game's highest professional title, and lives alone until nine-year-old shogi enthusiast Ai Hinatsuru shows up at his door insisting he already promised to be her teacher. Yaichi has no memory of making that promise, but takes her on anyway, and this manga adaptation follows the two of them navigating a professional shogi world that has little patience for a child apprentice.