The story follows two former friends and victims of bullying. One becomes a serial killer seeking revenge, while the other overcomes the trauma and becomes a police investigator, risking his life to catch his vengeful friend.
0 h 53 min
The investigation reveals links between the suspect and the detective, while the two detectives uncover Hwang Kyung's traumatic past.
0 h 42 min
The investigation reveals that Kyung-hyun's wife has been purchasing sleeping pills, while the latter prepares to take revenge on Ahn-jung.
0 h 50 min
Jung-suk remembers Kyung-hyun being bullied, while Jung-suk is warned that he could be the next target.
0 h 56 min
A special team is formed to capture Kyung, and Jung-suk uncovers suspicious activities at Sin-suk's company.
0 h 57 min
Jung-suk confronts Kyung-min in the parking lot, while Jin-ah discovers evidence at the video site.
0 h 53 min
Jung and Kyung buy new PE uniforms, and Kyung admits he's targeting Kang's ex-partners.
0 h 53 min
Jong-suk is ordered to remain silent for losing his weapon, and Jong-suk and his team raid Sin-suk's company.
0 h 58 min
Kyung offers Officer Park money in exchange for his help in getting revenge, and Jung interrogates Kang's bank client.
0 h 48 min
Kyung and former officer Park plan revenge on Chan-young, while Kyung sneaks into Park Chan's apartment.
1 h 4 min
Choi sees his mother helping their teacher into a taxi, while Park Chan's kidnappers are caught.
0 h 51 min
Park Chan's electrocution is revealed, and Kyung Min surrenders at a press conference.
1 h 4 min
Park Sung-Kyung rescues Min from a submerged car, and Kyung-Kyung kidnaps school principal Choi Suk-Ji.