Na HwaJin was sent by the ministry to a troublesome school on Jeju Island. The students are violent towards each other and the teachers, even resorting to threats, damaging teachers' cars, and invading their homes over poor grades. HwaJin infiltrates the school as a substitute teacher and introduces himself in the classroom, but the students completely ignore him. "Good morning, my name is Na HwaJin, and I'll be your substitute teacher for the next couple of days." Na said with a smile.