It all starts from the murder case from five years ago that Do Chang was in charge of.

Words get out of Incheon Seobu Police Station revealing that Lee Eun Hye, the daughter of a murderer Lee Dae Chul, has been kidnapped, murdered, and buried by a man who claims to be the culprit. As the news goes viral, people who were related to the murder case from five years ago tremble in fear of possibilities of getting brought to justice.

The execution of death-row convict Lee Dae Chul nears as well as the evaluation for Do Chang’s promotion. Knowing that Lee Dae Chul has an alibi at the time of the murder, Do Chang needs to decide whether to save an innocent man or to submit to the authority. Meanwhile, Do Chang and Ji Hyuk are joined by Seo Gyeong at Dae Chul’s old workplace, and that’s when Seo Gyeong gets a phone call from Park Gun Ho, who seemed to sound very urgent.

A big body of corruption sweeps over Violent Crimes Unit Two with the higher-ups continuously pressuring them to turn a blind eye to Lee Dae Chul’s case. Meanwhile, Ji Hyuk saves Seo Gyeong from Jo Seong Dae who is suspected of killing Park Gun Ho. Eventually, clues that lead to Lee Dae Chul’s innocence start piling up as Do Chang decides to look into the case to clarify discomforting ambiguities.

Do Chang gets reinstated and returns to Violent Crimes Unit Two after coming to an agreement with Superintendent Moon. The team then focuses on Park Gun Ho’s case and stumbles upon Jo Seong Dae’s bloodstain at the murder site. This leads to the revelation of Chief Nam's wrongdoing as well as a possible connection to Oh Jong Tae. Just before closing in on Jo Seong Dae, the team catches the sight of the one behind the corruption.