Kouichi Shimaoka is the central figure around whom the story revolves. An ordinary commuter leading a mundane life, his existence is abruptly shattered when a female passenger on a crowded train falsely accuses him of molestation. Wrongfully arrested and branded a criminal, he endures the humiliation and injustice of being condemned for an act he did not commit. This traumatic experience festers within him, gradually warping his personality from that of an unnoticed everyman into a calculating and embittered individual. His primary motivation becomes exacting revenge upon the woman who ruined his reputation, a goal he pursues by deciding to truly become the molester he was once mistaken for. Two years after the initial incident, he boards a train not as an innocent traveler but as a man with a deliberate, predatory intent to violate the very person who wronged him. This choice defines his role in the narrative: he transforms from a victim of a false allegation into the willing perpetrator of the crime, blurring the lines between justice and depravity. His key relationship is with the accuser, whose identity drives his obsession; in the process of seeking her out, he also engages with other women who become entangled in his descent. The story charts his development from a man broken by an unfair system into one who actively embraces the label he was given, illustrating how a thirst for vengeance can dismantle a person’s moral boundaries. Kouichi possesses no supernatural or exceptional abilities; his only notable capacity lies in the premeditation and resolve to cross a line he once would never have approached, turning his own pain into a weapon.