South Korea, October 13, 1990. After President Roh Tae-woo announced the suppression of organized crime, Busan businessman Choi Ik-hyun (Choi Min-sik) was arrested for embezzling billions of won from hotel construction companies, and were also charged with intimidation, kidnapping and assault. Busan prosecutor Jo Beom-seok (Kwak Do-won) is in charge of the investigation, and specifically the murder of hotel owner Heo Sam-shik (Kwon Tae-won) by robber Kim Pan-ho (Cho Jin -woong), whom Ik-hyun is said to be related to.
Back in March 1982, Choi was a Busan customs officer who, along with his colleagues, took bribes and stole merchandise. After discovering 10 kg of hiropon (crystal meth) in a warehouse one night, he and his colleague Mr. Jang (Kim Jong-soo) approach a friend of Jang, the gang boss Choi Hyung-bae. (Ha Jung-woo), to sell it to the Japanese Yakuza with whom Hyung-bae has a relationship. Ik-hyun discovers that the younger Hyung-bae is also a member of the same Choi clan from Gyeongju and the two form a close relationship. Ik-hyun leaves his customs job and becomes a full-time businessman, with Hyung-bae taking care of the underworld and Ik-hyun protecting him with his high-profile connections.
In the mid-1980s, the two forced a nightclub run by Ms. Yeo (Kim Hye-eun) on Pan-ho's yard. After his humiliation, Pan-ho caused the club to be raided by the police and Hyung-bae arrested, although Ik-hyun was released by Hyung-bae using the Choi clan connection. with Seoul prosecutor Choi Joo-dong (Kim Eung-soo). In May 1987, Ik-hyun and Hyung-bae took their business to new heights, formally affiliated with Japan's Yakuza and linked to a hotel-casino, Daedong, is also on the field of Pan-ho. Pan-ho threatens a gang war with Hyung-bae, and Ik-hyun is forced to decide where his loyalty and survival lie. 
In desperation, Ik-hyun meets Pan-ho without Hyung-bae knowing to resolve the problems between the two gangs. A paranoid Hyung-bae, who is increasingly annoyed because Ik-hyun tries to overpower him, Ik-Hyun beat and kicks off the gang with a stern warning. When Ik-hyun was arrested by the prosecutor, he finally revealed all his connections to the underworld in order to save himself. However, he seems to have only revealed the whereabouts of Pan-ho, who has eluded the authorities. In order to survive, Hyung-bae reconciles with Ik-hyun and they plan to run away together after Ik-hyun is sent to America by his family. However, when they were escaping from Busan, the authorities caught up to them. It turns out that Ik-hyun also revealed Hyung-bae's whereabouts and played him all the time. Hyung-bae tried to kill Ik-hyun out of frustration but he was arrested and taken away. The prosecutor was awarded the presidential award for destroying organized crime in Busan.
Twenty years later, Ik-hyun's son is a law student graduating from Seoul University and joined the prosecutor's office. Despite fleeing from the law and living a lavish life, Ik-hyun still endures feelings of guilt for betraying Hyung-bae. While Ik-hyun was celebrating his first grandson's birthday with the rest of the family, Hyung-bae's voice was heard. Ik-hyun turned his face towards the camera and the screen went black.