Chan Chi-Lung has been an infiltrator in Cheung Mo-Hung's Hong Kong triad gang for many years. After a failure of a recent negotiation by Lung with the other three local triad gangs on behalf of Hung makes the latter suspicious of Lung's identity. Hung sets to wipe out every undercover cop in his gang and as a result many cops are caught and wiped out. Sensing the danger, Lung requests to put an end to his undercover career from his captain, Cheung. However, Cheung sends Lung to Mainland China to infiltrate a business of "Special Identity" trading instead. The business is run by Hung's best protégé, Sunny, who was Lung's previous buddy in the gang. Cheung promises to reinstate Lung's police identity in conclusion of the mission once Sunny's business breaks down. Lung agrees, and joining him are local police officer Fang Jing and her chief Lei Peng from the Mainland Chinese police force. But before they can get to Sunny, the latter suddenly vanishes leaving Lung exposed and in great ... Written by DooK

Detective Johnny Du is smart and agile. But his height of 5'4'' has hindered him from joining the G4 protection detail for the Chief Executive. His sassy girlfriend Angel bullies him all the time, leaving him depressed at work and at home. His helplessness soon attracts Vincent, the Devil Prince and Jim, the Angel to fight for his soul. Written by Jiilo Kim

Laughing is judged guilty of murdering gang lord Michael So and is sentenced to life imprisonment. Locked up behind bars, he meets the seemingly benign inmate Fok Tin Yam, a university professor in criminal psychology who is jailed for drug possession. Highly intelligent and manipulative, Fok reveals the power of his mind games by effortlessly subduing the violent prison bully. He also deduces that Laughing is sent to the prison on an undercover mission to find out the rogue cops within the police force. The clues lead him to inmate Chit, a former sergeant from the Narcotics Bureau who has been suffering from a mental disorder. To unlock the critical information from the deranged man, Laughing must get the help of Fok, but this enigmatic figure has an agenda of his own...