Brave Citizen

So Shi Min was a promising boxer during her student days. She now works as a substitute teacher at a high school. Her only goal is to become a tenured teacher at the high school. To accomplish her goal, she maintains her tunnel vision and ignores troubling situations at the school. Nevertheless, she confronts Han Su Kang, who frequently gets into fights and is the most troubled student at the school. After witnessing intolerable violence, Shi Min decides to take justice on her own fists while putting on a mask to protect her identity and job.