Worried about her socially awkward son, Mei Itsukai invited his classmate Hayashi over after hearing he had no friends at school. Hayashi was a top student, well-liked and trusted by teachers, and Mei believed he would be a good friend for her son, feeling relieved. However, beneath his friendly exterior, Hayashi harbored a hidden malice he kept from everyone. Manipulating Mei's trust and lowering her guard, he gradually made his move... A sinister plot threatening her son's future begins to unfold.