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
Chi-hyun kills and buries Yun-ho, whose body is discovered following an anonymous tip. However, the caller conceals his identity, and the police are unable to obtain information about the perpetrator.
Tae-jin goes to meet Jong-soo but is attacked by Chi-hyun and collapses. Jong-soo, Geumhyeong Group's successor, is furious upon learning that Tae-jin has been skimming money from drug sales and demands to know where the money is. Tae-jin explains that only Jun-seo knew the password to the account where the money is stored, but he is dead.
Jong-soo orders Chi-hyun to bring drugs so they can blackmail Tae-jin and Sang-ui by poisoning them. While Chi-hyun is away, Sang-ui regains consciousness and knocks out Jong-soo. Sang-ui and Tae-jin manage to escape unharmed. Determined to take everyone down, Tae-jin gives Sang-ui one last chance, offering him 12 hours to flee the country.
Tae-jin then launches an all-out attack on Geumhyeong Pharmaceuticals and Jong-soo, initiating a raid as a prosecutor at the Anhyeon District Office. He pressures Geumhyeong Group and confronts Chairman Won, Jong-soo’s father, with a proposition: hand over Jong-soo and the group will be spared. Ultimately, Chairman Won decides to abandon his son, and Jong-soo is arrested in front of his father.
Jae-kyung and Yun-jin follow Jun-seo’s trail and obtain a USB containing crucial evidence. Jae-kyung’s past is also revealed: during their school days, he reported Jong-soo and his Inner Circle friends to the police after learning they killed Kyung-tae, while Jun-seo was unable to make a decision. However, this backfired and led to Jae-kyung’s forced transfer.
Jae-kyung’s subordinate, Chang-soo, is arrested on charges of a drug middleman's murder. The restored black box footage reveals that his testimony was false, leading to his arrest.
The team leader and Jae-kyung of the Narcotics Team at Anhyeon Police Station plan to capture Gong Jin-wook, who is attempting to flee to China by boat. To avoid civilian casualties, the team leader disguises herself as a stowaway to board the boat. However, their plan is leaked, resulting in the disguised officer being stabbed. Jae-kyung chases Gong Jin-wook with a gun, but he manages to escape and board the boat alone.
Jae-kyung narrowly succeeds in shooting Gong Jin-wook, stopping the boat. However, his colleagues, having discovered his drug addiction, arrest Jae-kyung, bringing Episode 13 of "Connection" to a dramatic end.
