Kurebishi Sora, a professional shogi player, had a traffic accident the day before his title match, and was reincarnated as Cress, the eldest son of a noble in another world. In that world, a game similar to shogi called "Board Monarch" is popular regardless of one's wealth and status. Cress, who makes full use of his shogi brain, has been dubbed a "child prodigy." Every day was filled with joy since as he was surrounded by a loving family. That is until one day that happy life suddenly collapses.