Gino Felino (Steven Seagal) is an NYPD detective from Brooklyn who knows everyone and everything in his neighborhood. He grew up in the neighborhood as a poor kid surrounded by wiseguys and made men but decided to become a cop. Gino has ties to everyone in the neighborhood, including the mob, and he has an understanding with them that neither will harm the other.
In the opening scene of the movie, Gino and his partner Bobby are waiting to bust up a multi-million dollar drug deal. Gino sees a pimp beating up a woman and intervenes; Gino promptly disposes of him. When he throws the pimp through the windshield of his car, we see red pimp shoes sticking out and then the iconic shot from the point of view of inside the car of Seagal scowling.
Shortly afterwards, we see the film's main villain, Richie Madano (William Forsythe), murdering Gino's parter Bobby Lupo on 18th Avenue in Bensonhurst, Brooklyn in broad daylight in front of his wife and two kids. Everyone knows that the killer is Richie, a crack addict who has been Gino's and Bobby's enemy since childhood. Gino knows Richie is not going to leave the neighborhood and he tells his captain (Jerry Orbach) that all he needs is an unmarked police car and a 12-gauge shotgun. His Captain gives him the clearance, providing Gino with a Remington 870 pump action shotgun and a brand new 1990 Chevrolet Caprice 9C1 from the Brooklyn 65th precinct. Gino visits his mob connection Frankie and his boss Don Vittorio to tell them that he is going to find Richie, while they want their own revenge on him for killing a cop on their streets. Gino starts the hunt for Richie at a bar run by Richie's brother Vinnie Madano. Vinnie and his friends all refuse to provide information, so Gino assaults all of them until they (including the local legend known as "Sticks") is a bloody heap on the floor. He still doesn't know where Richie is, but their attitude problem has been taken care of.
After visiting a number of local hangouts and establishments trying to find information, Gino eventually discovers that the reason why Richie killed Bobby is because Bobby was having an affair with two women - Richie's girlfriend Roxanne Ford (Julie Strain), and a waitress named Terry Malloy (Shannon Whirry). When Gino goes to Roxanne's home, he finds Roxanne dead. Gino believes that Richie killed Roxanne before killing Bobby. Gino goes to Laurie's house and tells her what's going on. In Laurie's purse, Gino finds the picture that Richie dropped on Bobby's body after killing Bobby. It turns out that Bobby was a corrupt cop who had wanted a money-making lifestyle like Richie's, and Laurie knew Bobby was corrupt. Laurie had found a picture of Bobby and Roxanne naked, and Laurie had given Richie the picture out of jealousy, never expecting Richie to kill Bobby for sleeping with Roxanne. Laurie took the picture away from where Richie dropped it on Bobby because she wanted to protect Bobby.
Gino attempts to get Richie out of hiding by arresting his sister Pattie (Gina Gershon) and by visiting his elderly parents. But because Richie is in a drug-fueled rage and basically intent on going down in a blaze of glory, there is little Gino can do except confront him. Thanks to a tip from his local snitch Picolino, Gino eventually finds Richie in a house in the old neighborhood having a party with his goons. Gino kills all of Richie's men (while suffering a gunshot wound in the process) and has a bloody showdown with Richie. Gino beats Richie senseless and then finally kills him by stabbing him in the forehead with a corkscrew.