Rising to their feet, Hinako, Makoto, Yoshi, and Yuki, the protagonists, respond to a summons from the principal. Upon arriving, the group is confronted with alarming graffiti that decorates the school walls. Of particular concern is a menacing message that threatens Makoto's life. They are entrusted with the responsibility of uncovering the author of the graffiti and safeguarding Makoto from harm. As the investigation unfolds, the group faces dangerous situations and puzzling mysteries.