Based on real-life crimes that terrorized Hong Kong in the 1990s, Logan (Tony Leung Ka-Fai) is the head of leading a notorious human trafficking gang, abducting the children of Hong Kong's elite. Police forces decide to send in Sky (Louis Koo), a Hong Kong undercover agent whose mission is to infiltrate and save the hostages, all while bringing the gang and their leader to justice.

An illegal immigrant from Mainland China sneaks into the corrupt British-colonized Hong Kong in 1963, transforming himself into a ruthless drug lord.