Newly appointed female teacher Yuu falls victim to a cunning trap set by the grade supervisor, losing all means of resignation. Forced to endure repeated humiliation and compulsory servitude in her daily life, Yuu is driven into the role of the supervisor's private sex slave at school. Once her secret is discovered, her students, colleagues, and even the school janitor begin to exploit and torment her one after another. With tears in her eyes, Yuu is transformed into a being whose sexual desires can only be satisfied within the school grounds.