Cast
Ji Sung as Jang Jae-kyung, a detective of the Narcotics Team at Anhyeon Police Station
Jeon Mi-do as Oh Yun-jin, a social affairs reporter of the Anhyeon Economic Daily
Kwon Yul as Park Tae-jin, a prosecutor at Ahn Hyun District Office
Kim Kyung-nam as Won Jong-soo, Geumhyeong Group's successor
Yoon Na-moo as Park Jun-seo, the central figure in the incident
Jung Yoo-min as Choi Ji-yeon, Jun-seo's wife
Jung Jae-kwang as Kim Chang-soo, Jae-kyung's teammate
Cha Yup as Oh Chi-hyun, Jong-soo's chief secretary
Jeong Soon-won as Heo Joo-song, CEO of Two Star Holdings, an insurance company
Park Geun-rok as Jung Sang-ui, a researcher at Geumhyeong Pharmaceutical
Jae-kyung is arrested on charges of drug addiction. The team leader of the Narcotics Team at Anhyeon Police Station privately questions him about everything that happened during his addiction. She then suggests that Jae-kyung falsely reports that he got addicted while on duty as a way to escape the charges.
Fortunately, Kim Chang-soo, who has always respected Jae-kyung, falsely confesses that he was the one who got Jae-kyung addicted, thus saving him. As a result, Jae-kyung’s addiction is officially recorded as an on-duty accident.
Tae-jin visits Jong-soo in prison, whom he had arrested, and tries to sow discord between Jong-soo and his father, Chairman Won of Geumhyeong Group. Jae-kyung arrests Chi-hyun on charges of murdering Jeong Yun-ho.
Gong Jin-wook, a drug distributor, comes to his senses in a hospital bed and testifies to the police that the "Doctor" is Park Tae-jin, based on information he received from Sang-ui over the phone.
Sang-ui, a researcher at Geumhyeong Pharmaceutical, begins to confront Tae-jin, a prosecutor at Anhyeon District Office, who tries to pin all the blame on Sang-ui. Sang-ui meets Tae-jin at a hideout for Inner Circle, where Tae-jin assaults him. At the same time, Jae-kyung, having been contacted by Sang-ui beforehand, arrives at the hideout.
Jae-kyung questions Jun-seo about what happened. Tae-jin had manipulated the relationship between Jong-soo and Jun-seo and tried to persuade Jun-seo to sell drugs with him. Desperate to pay for his daughter's medical bills, Jun-seo agreed to work with Tae-jin.
Jae-kyung accuses Tae-jin of being Jun-seo’s murderer. Drunk with triumph, Tae-jin arrogantly admits everything in front of Jae-kyung and Sang-ui. Enraged by the truth about Jun-seo’s death, Sang-ui pulls out a gun and shoots Tae-jin in the head, killing him.
Jae-kyung confronts Chairman Won about Jun-seo. It turns out that Jun-seo had approached Chairman Won before his death, asking him to make his friends pay for their crimes. Chairman Won then called Tae-jin and conveyed Jun-seo’s words, manipulating events to have Jun-seo killed.
Jae-kyung pressures Chairman Won and eventually gets him to confess that he was the mastermind behind Jun-seo’s murder, orchestrating it through his assistant at a construction site. Chairman Won is finally arrested.
Jae-kyung successfully proves that Jun-seo was murdered, and a large insurance payout is deposited to Jae-kyung and Yun-jin. They share part of this money with the wives of their two deceased friends. In the end, they manage to access the account where Tae-jin had stashed his drug money, bringing the series to a close.
