Reiko is a young woman who suffers molestation during a train incident, resulting in her mistakenly accusing protagonist Kazuo Sugimoto as her assailant. Her false accusation triggers Kazuo's confrontation with the actual perpetrator, Matazou Kamiya, and his subsequent apprenticeship under Matazou. Reiko's role remains confined to her experience as the complainant in this initial event, setting the plot in motion without involvement in Kazuo's later journey into "Chikan-do: The Way of the Groper."