Marcus Reed is a gangster that happens to be in his father's gang. In one night, he and his father were betrayed by Kev Lar.
In a Christmas night, Marcus goes to Lar's house to get revenge. He fights through his gang until getting to Lar, killing him. Just as one of the members is about to kill Marcus, Terry Higgins, his father's best friend, comes to the rescue. He asks Marcus what happened and the latter replies that he is betrayed and that the people he killed don't deserve to live. Terry is not liking Marcus for killing all of the gangsters and warns him that this will be the last time he'll save him or he is on his own for the rest of his life. Before leaving, Terry greets Marcus a Merry Christmas.
In 5 years later, Marcus gets a job of being a cop in the NYPD, something that Victor Navarro doesn't like. Terry reminds him of the contract, and Victor tells him to handle Marcus.
After passing a test, Marcus is taken to see his father in jail. While waiting for Terry, who has a business matter, an explosion occurs, leading Marcus to think that Terry is killed.
Angered by his mentor's death, Marcus swears revenge.
Good cop ending
Marcus and Whitting have Victor go to his locker at the Grand Station. When Whitting tells him that he has a search warrant for the locker, Victor tells him that he will find only his clothes and golf club. While opening the locker, Victor tells Marcus that when the case is over, he will wish that he didn't cross him.
After opening it, Victor taunts Marcus, asking him if he's happy for searching it. Just then, a bag of money drops, leading Victor to be arrested. Whitting tells Marcus to have some rest.
In the subway, Marcus is greeted by Terry, who happens to be alive all this time. He realizes that the latter is the mole. Because Whitting is after him, Terry fakes his death and has framed Victor for that crime. Marcus unknowingly protected his former mentor from the gangs. Terry tries to get him to leave with all of the money, but Marcus is angered by his betrayal.
Angered by his righteous attitude, Terry gives Marcus pictures of his rampage 5 years ago and uses it to warn him of not telling of his criminal activities. Marcus pursues him afterwards.
Terry escapes, but Marcus shoots continuously into the train, killing the former in an explosion. Marcus escapes.
Just as Terry's body is carried in a stretcher, Whitting tells Dixon that Marcus deserves a promotion. However, Marcus plans to have his father released from jail instead and leaves the subway.
Bad cop ending
It is like the good cop ending except for the few parts. While Victor is arrested, Marcus insults him, prompting him to kill Whitting in a rage. Marcus pursues Victor to a train and gets into a fistfight with him. He throws Victor off the train, killing him.
Just as Victor's body is carried in a stretcher, Dixon is so shocked about what Victor has done because he is in the force for 30 years. She tells Marcus to have some rest.
In the subway, Terry arrives and Marcus tells him that he knew that he is the mole all along. When Terry asks Marcus that if he knows that Victor is innocent, why did he kill him? The answer is that Marcus never liked Victor.
Marcus is angered by Terry's treachery as Terry explains that Whitting is after him and tries to get him to leave with all of the money. Marcus pulls his gun into Terry's head and kills him. He gets all of the money. However, just as he is about to leave, Marcus stays in the subway to stare at his badge in shame, waiting for punishment for being disloyal to the force.