In this prequel to Mou gaan dou (2002), Chan Wing Yan has just become an undercover cop in the triads while Lau Kin Ming joins the police force. Both the triads and the police find an enemy in a rival crime boss.
The story tells the story of Sun Wukong (Eddie Peng) and Erlang Shen (Shawn Yue), who comes to the Immortal Mountain to cultivate their skills. They gained friendship, experienced love and ultimately betrayal, growing throughout their life journey.
A portable nuclear device, DC8, has been stolen from South Korea by a ruthless criminal (Chang Chen) and his accomplice (Janice Man). As the weapon will change hands in Hong Kong, Lee (Nick Cheung) from the territory's Counter Terrorism Response Unit sets up a task force, which includes police officer Fan (Shawn Yue), to deal with the crisis. He enlists physics professor Siu (Jacky Cheung)...
A cop-turned-bar owner befriends a drunken woman at closing hours and finds himself pursued by her former lover and the thugs he employs. The chase turns deadly when the bar owner's deadbeat brother and a suitcase full of cash enter the picture.