When Hong Kong is rocked by multiple gruesome murders, the police forms a task force to investigate. Jun, once a brilliant detective who suffered a mental breakdown, begins his own investigation. Eventually, the police learn that the murder victims are all suspects of cold cases being rubbed out by a figure known as "The Sleuth". Now, Jun and a detective from the task force are on a race against time to beat the brutal killer at its own game.
In 1990, Neurologist Lam Sik Ka and his former flame suffer from the generational sleep curse that rooted in their both families war engagement during World War Two. Lam tries to save her flame from the grudge.
In 1970s Hong Kong, the Independent Commission Against Corruption (ICAC) was formed to bring down the corruption syndicate led by British government officials. One of its top investigators is Senior Investigator Lau Kai-Yuen, who brought down countless corrupted officials. Just as he thought stability and prosperity are within reach, a new era of greed and riches takes him into a new battlefield of corruption.
