Her husband is a teacher, and Yui comes to his school for her teaching practicum. Trying to keep their marriage a secret, Yui begins her training, but the secret quickly unravels. The vice-principal, Takagi—whom she once regarded as a mentor—discovers her weakness and uses it to control her, leaving Yui powerless to resist no matter how much she pleads. She is tormented by him relentlessly, whether during class or after school. His abuse grows increasingly severe, and soon the delinquent student Ioka finds out about their relationship. Yui begins to feel her life can never return to the way it was.