해준과 윤영에게서 수상함을 느낀 우정리 형사 동식. 윤영은 신분위조를 위해 해준이 교사로 위장전입한 우정고등학교에 학생으로 전학가게 된다. 그리고 학교엔, 해준이 쫓던 연쇄살인의 진범으로 의심되는 인물들이 하나둘 등장하기 시작한다.
Yoon-young was able to enter school thanks to Hae-jun's help. As soon as she began her classes, she realized that one of her classmates was the future Ko Mi-sook. However, she was unaware of the danger that Ko Mi-sook posed, as she was extremely clever. Hae-jun ensured that Yoon-young remained at school until he could pick her up, but when he returned, Yoon-young was nowhere to be found.
