A sexual scandal between a math teacher and a student in a prestigious high school ended in tragedy. 4 years later they meet again, now as adults, to reveal the corruptions in school and to regain one's reputation as a teacher.

Lim Soo-jung, Lee Do-hyun, Jin Kyung, Woo Da-vi, Jang Hyun-sung, Byeon Jung-su, Choi Dae-hoon, Baek Ji-won, Kim Ho-jin, Jeon Guk-hyang, Oh Hye-won, Lee Kang-ji, Kim Ji-young, Oh Kwang-rok, Han Gi-joong, Choi Seung-hoon, Jang Gwang, Son Jin-hwan, Jeon Jin-gi, Yang Jo-a, Ahn Sang-woo, Choi Woo-sung, Lee Young-eun