Hui Chun-sum is an elite OCTB officer. He is fearless and competent. His boss thinks highly of him, and his colleagues really admire him. But his ultimate dream is to join SDU. Another elite OCTB officer Shum Wai-lik has a shrewd mind and extensive experience. Although the duo have different approaches, but they are like-minded and ideally complement each other. Police suffer heavy casualties as they are ambushed by thugs. To catch the culprit, Chun-sum forgets his dream and stays with OCTB. Moreover, Chun-sum and Wai-lik are faced with successive nasty cases that are tortuous, surreptitious, tricky and baffling. The duo use reverse thinking, psychological game theory and meticulous analysis to decipher the criminals’ thoughts and motives. No crook can escape the long arm of the law!

A thrilling story revolving around a policeman who becomes embroiled in a conspiracy plaguing the high-ranking officials due to an incident that almost cost him his life.

In some faraway place, the Laws and the Chuks are two big families that have been foes for a century as they can never stand each other. In a chance encounter, the Law Family’s fourth son Law Mak-au falls head over heels in love with Chu Lai-yip, who is the younger cousin sister of the Chuk Family’s matriarch Chuk Ying-kiu. Lai-yip already has a finacé. If her marriage eventually falls through, Ying-kiu’s status as the chair will be affected. However, due to some past event about herself, Ying-kiu resolutely decides to let Lai-yip make her own choice, sowing the seeds of a duel between the two families. In the meantime, Leung Shan-pak adopts Max Ton as his name and lives in Hoi Pak City, which is the Law Family’s territory. To avoid assassins, he goes to the Chuk Family’s Tin Nam City and then the mysterious Zone 8. He again runs into two women who were seemingly associated with him.

Following the success of part 1, "Sinister Beings 2" returns with a familiar cast. Two senior detectives Hua Tuan Sam (played by Tran Trien Bang) and Tham Vi Luc (played by Huynh Tri Hien) work together for the Organized Crime Investigation Team and the OCTB or Point O (Organized Crime and Triad Bureau). With their intelligence and sharp observation ability, they solve many cases.