[Chor Au Kuen/左勾拳(Ruco Chan/陳展鵬)] bears the pain and grief of losing his family and returns back to the walled city in hopes of finding his long lost older sister. The place he once grew up in has turned into a lawless jungle riddled with crimes.
In order to restore law and order within the walled city, Chor Au Kuen unites everyone by setting up a neighborhood welfare association to fight against the criminal forces. As a result, he clashes with Yuk Bo Fung's son [Yuk Bo Fung/龍成虎(Philip Ng/伍允龍)], who's an underground fighting champion.
Just as everything is starting to get back on track, a key figure in the triad mysteriously dies under the attack of a Bajiquan master. Chor Au Kuen and Tiu Lan join forces to investigate the matter and discover striptease group leader [Fa Man/花曼(Grace Wong/王君馨)] was behind the attack. At the same time, the truth behind the death of Chor Au Kuen's father is also unraveled. However, one thing that Chor Au Kuen can't get over is his friend is secretly a member of a merciless assassin group. Now, he's forced into a fight of his life with his best friend that was supposed to happen 15 years ago....