S1, E1: Prosecutor Cho Changsik receives a request from Japan for a joint investigation into the flow of drugs from Korea. He assembles a team of investigators and suspects a connection to Gangnam Crystal, the new drug spreading in Gangnam.

S1, E1: Prosecutor Cho Changsik receives a request from Japan for a joint investigation into the flow of drugs from Korea. He assembles a team of investigators and suspects a connection to Gangnam Crystal, the new drug spreading in Gangnam.