After three years of failing college entrance exams, a desperate ronin enters his fourth year of preparation, sinking deeper into self-destructive despair. Suddenly, a mysteriously beautiful private tutor appears before him—Yuri Sato. This seductive instructor has no intention of helping him study; instead, she's a corrupt teacher whose goal is to lure students into sexual submission and academic failure. During lessons, she exposes her breasts, flashes her panties, and completely distracts him from studying. Whenever he fails to solve a problem, she punishes him physically, then forces him into a chastity belt—claiming he must "expel learned knowledge through masturbation"—thereby denying him release. Tormented by endless arousal, he's made to perform cunnilingus on her while she selfishly indulges in pleasure. Repeating these cruel acts, she ensures his exam failure, preserving her position as a tutor while satisfying her greed for money and sexual dominance. Now, her first lesson is about to begin. Will the ronin fall into the beautiful tutor's trap, or can he break free using his own will? The moment of truth is here.