Yuri, a married schoolteacher, is strict yet caring toward her students and is widely respected and trusted by them. However, delinquent student Yano constantly defies her authority. After catching him cheating on an exam, she firmly scolds him, and following a heated argument, even slaps him in front of the class. Humiliated and filled with resentment, Yano begins plotting revenge against her. His scheme gradually draws in a female student, escalating into a dangerous conspiracy that threatens to destroy Yuri's life.