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.

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.

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.