In the 1990s, a police officer goes undercover to infiltrate a mega crime syndicate that distributes illegal drugs across South Korea, China, and Japan. His wife, a narcotics officer, is also involved.
Cast:Ji Chang-wook , Wi Ha-joon , Im She-mi , Bibi , Ji Seung-hyun , Yoon Kyung-ho , Jeong Jae-kwang , Jeong Man-sik , Park Ji-hoon , Woo Kang-Min , Lee Shin-Ki , Cha Rae-hyung , Kim Beom-soo , Han Yi-jin , Lee Jung-hun , Lee Han-ju , Jo Deok-hyeon , Ko In-beom
Detective Junmo goes undercover within Gangnam Union to probe an international drug trade.
Barely passing Gicheul's test, Junmo joins Gangnam Union and discovers an unexpected truth.
Euijeong's appearance puts the squad in trouble. Gicheul finds last night's attack suspicious.
The team seeks Eui Jeong's aid to assist Jun Mo in a crisis, which leads to a perilous love triangle.
Earning Gi Cheul's trust, Jun Mo becomes anxious as he sees Gi Cheul making a move towards Eui Jeong.
The delivery accident has put the trade on risk, While Detective Hwang closely monitors the Gangnam union.
Haeryun shows interest in Junmo; Euijeong approaches Gicheul; Junmo takes an extreme measure.
Kicheol suspects Junmo. The four people's irreversible decisions trigger the biggest crisis.
The battle with Jaegeon creates a crack. Junmo joins forces with Haeryun to resume the trade.
Junmo and Euijeong juggle duty and feelings. Hwang continues to meddle, and the final day arrives.
An accident halts the trade and a crisis approaches as Euijeong and Dohyung worry about Junmo.
Gicheul and Junmo make their way to the final deal. Korea, China, and Japan prepare for the arrest.