In 1980s Hong Kong, troubled youth Chan Lok-kwun, a mainland refugee, struggles to survive in the Kowloon Walled City by joining underground fights. Betrayed by crime boss Mr. Big while trying to buy a fake ID, he steals drugs from him and seeks refuge in the Walled City, where he encounters Cyclone, a compassionate yet authoritative crime lord.

A washed-up action choreographer, struggling to find his way in a changing industry, risks everything to stage an epic comeback, and attempts to repair the relationship with his estranged daughter before it's too late.

“Once clothed as an official, you represent law and justice.” This was taught to young detective Xian who worked under Detective “Silent Dog” Ao to catch mountain robbers. To everyone’s dismay, the robbers turned out to be detectives from neighbouring counties who were forced to rob the ruling county to save the poor. Through trickery and lies, Ao started a bloodbath to kill the robbers. Shaken to the core by Ao’s deceit, the originally naïve Xian abandoned his dreams to uphold righteous values. Not to be outdone, he ended up murdering the treacherous Ao for his own gains. With blades and blood, Xian was later hailed as a legendary detective.