Axel Stone, a vigilante who recently quit the police force, is late for a meeting with Officer Murphy, a good cop, after fighting some drug dealers. Murphy returns home, unable to provide Axel with a disc capable of bringing down the entire police department. When informed that his grandson, Skates, is coming home from prison, Murphy calls him a disgrace. At the local bar, Roach is causing trouble by vandalising a pinball machine and threatening the owner when Skates arrives, fresh out of prison. The gang heads out to get some beers. Elsewhere, a meeting is going on, courtest of Mr X, trying to decide what to do with several people not interested in being corrupted. Attention is brought towards the situation of Murphy, a policeman planning to expose their operations. The chair of the meeting wants the disc destroyed and Murphy dead.
In a local store, Officer Murphy and the shop owner are gunned down by hooded, corrupt cops. Good police arrive on the scene but the two are already dead. Later, the group of vigilantes find Skates, apparently after his stepdad's plight had already been revealed to him. They know of the disc and need Skates' help to find it, but he isn't interested. Getting home, Skates finds his house trashed and his mum beaten, the crooks looking for the disc, but they didn't check the toilet cistern. Skates heads to call 911, but he realizes there's nobody left to trust. At a geek's house, Skates looks up the disc's content and realises that it contains a list of corrupt policeman and all their crimes. He heads to find his friend, Roach, but he isn't interested in dealing with cops who kill other cops. Taking matters into his own hand, he climbs ten stories up the side of the police department HQ and records a conversation, but he loses his grip and is caught by one of the officers inside. Later, the officers destroy the disc and take him to someone who knows how to kill with style. Elsewhere, the vigilantes are questioning Rizzo, a corrupt policeman who knows nothing about the disc, but does know about a bomb plot.
On board the Princess Grace, Mr X is holding a charity ball. Max is busy looking for the bomb but is having little luck. Meanwhile, the police pull up to some crooks and we find that it is Roach that has been hired to kill Skates. Instead of going through with it, he turns his gun on the cops. As one dies, he reveals the bomb plot. Skates wants to help, but Roach is having none of it. Back on board the boat, Mr X has gone missing. Ready to board his helicopter, he knows he has won.
The only hero who knows where the bomb is, Skates dives into the ocean and follows the boat. On board, Axel, Blaze and Max confront Mr X, knocking out his bodyguard and Axel points his gun at X. Down below deck, Skates has found the bomb and, as the helicopter pilot leaves without Mr X, Skates somehow destroys the chopper and his arrival is welcomed gleefully by Max. Mr X is frantic, however, when he reveals that a second bomb is strapped to a tied-up worker on the ship. With no time left, the explosion rips through the ship.
The passengers fly into the air, the majority presumably dead. On a floating piece of debris, Skates has Mr X at gunpoint. Before he can shoot, the police arrive and warn Skates not to shoot. The vigilantes do the same and Skates has no choice but to surrender, commenting he must be going soft. On the news the next day, the reporter reveals that Mr X has been in court on several charges of murder, extortion and kidnapping. The geek who's computer Skates used had made a back-up of the disc which incriminated the corrupt cops. When asked if Skates wanted to become a cop like his dad, he laughs it off, not wishing to do so in "this stinking city". In front of a wall of wanted criminals, some crossed off, Max asks if Skates wants to join them. In his usual cocky attitude, Skates accepts, before skating off into the night.