Undercover agent Yuki Himemiya infiltrates Tokudo Academy to take down a drug trafficking ring's mastermind, successfully defeating the culprit. For her next mission, she goes undercover at Aisho Academy. While investigating in her school uniform, she's ambushed by physical education teacher Kuma no, who overpowers her despite her yo-yo weapon, leaving her defeated. Kuma no, a former mercenary with immense strength, subjects Yuki to brutal torture. Enduring the sadistic and sexually degrading torment inflicted by the school principal, Yuki is eventually rescued by Makoto, the principal's son. But with Makoto's help, can Yuki finally defeat Kuma no and his allies? The climax focuses on how she endures extreme torture and life-threatening danger to complete her mission.