Mai is a serious and dedicated beautiful teacher. One day, she witnesses delinquent behavior by her student Kawagoe. When her warning is met with blatant disregard, Mai calmly slaps him across the face. As she leaves, she coldly remarks, "Don't play around. Or is that the best you can do?" That single slap changes everything—Kawagoe feels humiliated and consumed by rage. Enlisting his delinquent senior friends, he devises a twisted plan. Later, Kawagoe calls Mai, claiming he wants to apologize. Moved by his words, Mai agrees to meet him—unaware that her real torment is only just beginning.