
Set in the 1980s, a husband and wife, both detectives, infiltrate a massive criminal organization responsible for the illegal drug trade between Korea, China, and Japan.






Detective Joon Mo goes undercover within Gangnam Union to probe an international drug trade.
Barely passing Gi Cheul's test, Joon Mo joins Gangnam Union and discovers an unexpected truth.
The team seeks Eui Jung's aid to assist Joon Mo in a crisis, which leads to a perilous love triangle.
The team seeks Eui Jung's aid to assist Joon Mo in a crisis, which leads to a perilous love triangle.
Earning Gi Cheul's trust, Joon Mo becomes anxious as he sees Gi Cheul making a move towards Eui Jung.
The delivery accident jeopardizes the trade. Detective Hwang closely surveils Gangnam Union.
Hae Ryun shows interest in Joon Mo and Eui Jung approaches Gi Cheul. Joon Mo takes an extreme measure.
Gi Cheul suspects Joon Mo. The four people's irreversible decisions trigger the biggest crisis.
The battle with Jaegeon creates a crack. Joon Mo joins forces with Hae Ryun to resume the trade.
Joon Mo and Eui Jung juggle duty and feelings. Hwang continues to meddle, and the final day arrives.
An accident halts the trade and a crisis approaches as Eui Jung and Do Hyung worry about Joon Mo.
Gi Cheul and Joon Mo make their way to the final deal. Korea, China, and Japan prepare for the arrest.