After being promoted to the Metropolitian Investigation Unit, Detective Ma Seok-do and his colleagues look into the death of Go Sun-hee and determine from the autopsy report that Sun-hee had been using the drug “Hiper.” Ma visits the club and questions the owner, where they discover that a yakuza member by the name of Hiroshi supplies the club with Hiper from Incheon. Ma’s squad succeeds in apprehending Hiro and capturing 20 kilograms of Hiper, but a dishonest police officer named Joo Sung-chul steals the drug and kills Hiroshi, while Ma’s crew escapes the ambush.
In reality, Sung-chul is defending the White Shark Clan, a criminal organization who stole Hiper in order to profit. After learning that Hiper has been taken by the White Shark, the yakuza recruits Riki as a hitman to recover Hiper. When Riki kills Tomo and flees, Ma tries to capture him after learning about another drug dealer named Tomo. This starts a drug war between Riki and Sung-chul. Ma follows the clue to the boat yacht where they discover Hiper and, with the assistance of a friend, Cho Rong-i, negotiates a deal with Sung-chul.