After completion of a three-year undercover operation, Sit Ka-keung returns to Hong Kong, opens a foot massage place and continues to gather intelligence. Criminal Intelligence Bureau (CIB) Chief Inspector Cheung Kei-gee keeps Cheuk Hoi under close surveillance as she suspects Cheuk Hoi has become a gangster after being released from prison. Ka-keung and Cheuk Hoi are drawn into an organ trafficking case. They team up with female decoy Dou Ah-hei and Security Bureau Investigator Wai Chok-wing to crack down on the syndicate involved. Security Bureau then sets up Security Intelligence Agnecy and invites Chui Tin-tong to join their team and take the helm of CIB. Chum Foon-hei has managed to escaped death. He then covertly investigates secrets of some gang. Ngai Tak-lai, younger brother of deceased Cheung Hing head Victor, is actually the founder of the mysterious society. He is also plotting to take revenge on Ka-keung and Cheuk Hoi.