As a child, Shion Ishiwatari's parents were murdered in their own home. Shion escaped unharmed, yet the trauma caused her to lose her voice. The only evidence police found was a shougi board and one piece "the King". Neighbours and close friends of the family, Shinji and Sachiko Yasuoka, adopted Shion and taught Shion how to play shougi. As the years passed, she became known as a genius and quite a famous player. Now, as her fame rises, her past resurfaces and she discovers that being a professional shogi player may just lead to finding her parents' killer.