Jun Lee (Lau), a former police inspector and elite detective in OCTB, has been expelled from the police force after his severe mental breakdown and ensured chaos happened in police headquarters due to a wrongful conviction in the Butcher case and the Devil Cop case.

Years later, a series of high-profile murders happen, and a group of culprits who called themselves "The Sleuths" leave sneak peeks of their subsequent murders, which are connected to the cases that Jun has investigated.
 
Yee Chan (Choi), a fellow lieutenant inspector in OCTB, who was also the only survivor in the Butcher case 17 years ago, believes Jun is the only hope to crack the Sleuths and requests his help. The deeper they investigate the Sleuths' motive for the crime, they discover the secrets of past cases beyond their imagination.
 
NTSC: Widescreen 16:9
 
Cantonese / Mandarin
 
Chinese, English
 
Region All