Shion is the central character of the narrative. At the tender age of five, she witnessed the brutal murder of her parents within their home; however, the identity of the killer remains a mystery. This traumatic event left Shion mute, unable to speak since that fateful day. To convey her thoughts and needs, she resorts to writing notes. Among the chaos of the crime scene, Shion discovered a king piece from the game shogi, leading her to speculate that the murderer might be an aficionado of this traditional board game.
As the story unfolds, Shion is eleven years old (in the manga version) and attending junior-high school. She has a sweet tooth, with chocolate being her ultimate indulgence. Under the guidance of her foster father, Shion delves into the world of shogi, hoping that mastering the game will provide her with clues about her parents' untimely demise. Through this journey, she seeks not only to uncover the truth but also to find solace in the intricate patterns and strategies of shogi.
