Present day New York City: Sean MacArthur (Channing Tatum) is a street hustler. One day while selling counterfeit goods at the corner of Radio City Music Hall, a group of young men attempt to force Sean to relocate with his merchandise. These boys work for Harvey Boarden (Terrence Howard), a ticket scalper who controls the corner. Sean fights them off, but does not retain his money or products.
Later, Sean sees Harvey and the guys who stole his money in a cafe and confronts them. Harvey gives him his money back and offers him a chance at a “winner takes all” fight for money. Harvey sets up a meeting with his friend and rival, Martinez (Luis Guzmán). Sean’s first fight is at a Brooklyn church against a Russian. He wins when he knocks the Russian into a water fountain. Harvey takes Sean to a club where he meets a waitress named Zulay (Zulay Henao), a single mother to whom Sean had earlier tried to sell a fake Chinese Harry Potter book. In the VIP area to the club, Sean also meets Evan Hailey (Brian White), a professional fighter who used to be on the same college wrestling team as Sean and was coached by Sean’s father. Sean and Harvey leave after Evan and Sean nearly get into a fight. Sean’s second fight is at the back of a store in the Bronx, against a much larger opponent. The fight descends into chaos after some of Harvey’s crew interfere, when the opponent nearly chokes Sean, and the woman who owns the store pulls out a gun when one of the guys spills her drink. Harvey, Sean, and the rest of Harvey’s crew flee the scene and neither fighter gets paid. Sean’s third fight is at a penthouse in which Sean is victorious. Later in the day, he goes to a club to celebrate, Evan is there and instigates a confrontation with Sean and taunts him on his current status and his father.
Between fights, Sean continues to court and romance Zulay and they eventually have sex. Zulay later asks Sean on the subject of his family in which he tells her that the reason why he and Evan have such a bitter rivalry is because Sean’s father coached the wrestling team that he and Evan were in. Sean’s father showed more affection toward Evan while Sean was consistently bullied by other teammates including Evan. Having had enough, he lashed out at Evan and when Sean’s father tried to break them up, Sean explains that in a blind fury, he beat his father to a pulp and hasn’t seen or heard from him since the incident and knows he will probably never be forgiven. Sean and Zulay are later visited by Harvey, and Sean is furious, suspecting Zulay and Harvey of having sexual relations. Harvey explains that Zulay places bets for him.
Sean and Harvey are offered a fight against Evan, and Sean accepts, but Harvey wants him to throw the fight so that Martinez and his associates can make money. Sean agrees to throw the fight. Zulay places the bets, a total of $500,000. Sean and Evan fight, with Zulay, Harvey, and the rest of the crew watching. Evan has Sean in a chokehold and it appears that Sean is about to throw the fight; however, he fights back and overpowers Evan. Sean beats Evan, and Martinez threatens Harvey. At Harvey’s apartment, Sean reveals Zulay reversed the bets and they have one million dollars. Zulay picks up Sean and Harvey, and they leave New York with Zulay’s daughter and grandmother.