To preserve the legacy of the kendo club after all other members had left, Aika continued practicing alone. With her beautiful black hair and sharp, determined eyes, she spent her days training in solitude with her club advisor. One day, a senior who had already graduated invited her to private training sessions—only for Aika to be subjected to sexual acts disguised as coaching. The next day, memories of the session resurfaced in her mind, and she began masturbating alone in the dojo. Caught in the act by the school's disciplinary teacher, she was threatened with disbanding the club on grounds of "immoral conduct." To protect the club she had devoted her pure heart to, Aika's tragedy begins now.