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.

While clues proving a corruptive body’s close relation to Lee Dae Chul’s case pile up, Do Chang figures out a work-around to carry out a secret investigation on Jo Seong Dae. On top of that, Ji Hyuk hints to him how his very cousin, Oh Jong Tae, may be partially responsible for Yoon Ji Sun’s death from five years ago. Meanwhile, Dae Chul’s day of execution nears as his daughter, Eun Hye, visits him at the prison.

Do Chang confesses to Eun Hye that he wants to save her father, Lee Dae Chul. Unfortunately, Eun Hye can’t trust Do Chang who literally handcuffed and arrested her father for a murder he didn’t commit. However, Do Chang shows a sign of hope for Eun Hye by getting the re-trial approved. Meanwhile, Superintendent Moon and Yoon Sang Mi prepare themselves for the possibility of an unexpected turn of events.

Although Do Chang and Mr. So prepare for the retrial of Lee Dae Chul’s case, Do Chang still needs to persuade Dae Chul to follow his lead because he is reluctant to take part in it due to the possibility of harm that it may cause his daughter. Meanwhile, Do Chang finds himself caught in a dilemma that is inflicting harm to both the victims who lost their beloved partners and the ones who crossed the line for their greed.

It was already difficult enough for Do Chang and others to get a retrial approved. However, feeling desperate during the trial, Dae Chul falsely admits to his killing of Detective Jang Jin Soo. Meanwhile, Seo Gyeong receives a recording from an unknown sender of a conversation between Superintendent Moon and a prosecutor, which could act as solid evidence to prove Dae Chul’s innocence.

After losing at the retrial, Do Chang gets demoted. With Do Chang out of the picture, Violent Crimes Unit Two also feels pointless to even fight for a comeback. Meanwhile, Ji Hyuk meets Seo Gyeong and finds out about a voice recording that she’s been keeping secret. Ji Hyuk and Do Chang then indirectly threaten Superintendent Moon so that they can follow him and see where he would lead them.

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.