A pariah detective is pulled back into the game after his daughter's friend goes missing. The latest in a long line of women to go missing in the Gangnam area of Seoul, the detective delves back into a world of vice, drugs and corruption to uncover something that threatens to topple some of the city's wealthiest elite.
E1
In Gangnam, a call girl flees her pursuers as Detective Kang Dong-woo, Broker Yoon Gil-ho and Prosecutor Min Seo-jin investigate a missing persons case.
E2
A body at Gangnam Station prompts a Special Investigations Unit. Detective Kang reunites with Kim Jang-ho as Gil-ho suspects K-pop star Noh Joon-seo.
E3
Dong-woo investigates with evidence from Gil-ho and meets an unexpected figure. Seo-jin seeks help as the case deepens while Gil-ho gets unsettling news.
E4
Rescued, Gil-ho reveals the Colosseum is the key to the case. Jae-hee rushes to save her friend as Dong-woo and Seo-jin follow with their own motives.
E5
Jae-hee heads over to meet Choi Hak-gu to save Ye-seo, while Dong-woo and Gil-ho try to rescue Jae-hee.
E6
Seo-jin climbs the ranks with the help of Hak-gu while Dong-woo becomes a chauffer and hunts for Ye-seo.
E7
Gilho returns to Gangnam seeking revenge for Jaehee and runs into Dongwoo who is looking for clues to find Yeseo. Madam Suin learns about Yeseo's dangerous plan and decides to risk her life to save Yeseo and other girls.
E8
Jaehee's video is finally revealed, revealing the full story. Driven by love, revenge, and justice, every single one of them fight a battle against the cartel in their own way, for their own reasons.