"I've been searching for so long... for someone who'll punish me...!" A traditional club that exists at a posh girls' school. The name it goes by behind closed doors... the "Punishment Club." Alone in the club room after its members have gone, the girl Mio loses herself in masturbation, craving stimulation. One day she spots a sadistic gift in Ai, a transfer student... Begging, she is handed a harsh punishment every day. Ai, too, gradually awakens to the pleasure of domination... strap-on irrumatio, urine drinking, slaps and S&M training. Mio Ichijo, lesbian debut and masochistic awakening!