When Jo Gang-Ja attended high school, she was notorious for fighting. She gave birth to her daughter A-Ran in her late teens and became more responsible. Her daughter A-Ran is now a high school student, but A-Ran is bullied at school. Jo Gang-Ja decides to go back to high school to protect her daughter. Jo Gang-Ja becomes a high school student again.

Based on actual events that took place at Gwangju Inhwa School for the hearing-impaired, where young deaf students were the victims of repeated sexual assaults by faculty members over a period of five years in the early 2000s.

Sang-hwan became a cop in order to help the downtrodden, but he doesn't get much respect. All that changes when he meets the Seven Masters.