Young Ju carries out the interrogation with Bae Min Gyu, the victim's husband, but there is no solid evidence of the crime. Furthermore, his lover, Lee Eun Byeol submits a new alibi for him, and he gets released once again. Meanwhile, another hideous murder case occurs with a similar display.

A detective who was chasing the real culprit of a serial murder case faces the hidden secret of his family. Jin-sung is a cheerful yet nasty-tempered detective at Woojin Police Station who fights for justice with all his heart. Meanwhile, Young Ju is a competent prosecutor with a high winning rate who believes that injustice must be punished through injustice. She is also an old friend of Jin-sung and Jin-woo. Jin-sung transfers to a special investigation team in Seoul for serial murder cases and carries out the investigation with Young-ju. However, Jin-woo, Jin-sung's brother, gets arrested as a suspect of the serial murders.

Jin-woo gets released and Jin-sung manages to obtain crucial evidence to arrest Bae Min-gyu. However, when the arrest warrant was issued, another suspect of the three serial murders appeared. Meanwhile, Jung-sook wants Young-woon to quit his job and move to the US with the family.

On a stormy night, Jin-woo gets into an accident at the seaside. Jin-sung and Young-ju get help from Jung-sook to transfer him to Jinjin Medical Center in Seoul. He may be brain-dead in the worst-case scenario, but Jin-sung and Young-ju believe that he will wake up. Meanwhile, Young-woon is being sent to training abroad as a reward for solving the serial murder.

Jin Sung receives two videos sent by an anonymous sender, and he’s shocked to discover that the videos show his brother Jin Woo being murdered. Similarly, Ko Young Ju also receives a video of a murder with a warning that the real culprit is someone else. These revelations lead the special task force to reopen the case, and they uncover new leads in their investigation.