Mia Nanasawa, a beautiful girl entering her rebellious phase, finds her sensitive heart consumed by an uncontrollable urge to peek at penises and crave sperm. With the arrival of her private tutor—the "new toy"—she resolves to transform him into her obedient slave over the course of 100 days. Despite her mother being right there in the house, Mia boldly jerks him off in hidden corners behind textbooks, rides his face without hesitation, and spirals into increasingly wild behavior. The tutor panics, desperately trying to hide the girl's vaginal fluids smeared across his face before her mother notices. Whenever he cums too quickly, she punishes him by forcing him to squirt like a man over and over again. Through each sadistic session, he gradually succumbs exactly as Mia intended—morphing into her perfect submissive servant.