- Jun Lee (Lau), a former police inspector and elite detective in OCTB who has been expelled from the police force, after his serious mental breakdown and ensured a chaos happened in police headquarters due to a wrongly conviction of the Butcher case and the Devil Cop case.
Years later, a series of high profile murders happens, and a group of culprits who called themselves "The Sleuths" leaving the sneak peeks of their next murders, which connected to the cases which Jun has investigated into. Yee Chan (Choi), a fellow lieutenant inspector in OCTB, who also the only survivor in the Butcher case 17 years ago, believes Jun is the only hope to crack the Sleuths, requests his help. The deeper they investigate of the Sleuths' motive of crime, they discover the secrets of the past cases beyond their imagination.
Ka Fai Wai
Sean Lau Ching Wan
Raymond Lam Fung