Small-town boy Shawn MacArthur (Channing Tatum) has come to New York City with nothing. Barely earning a living selling counterfeit goods on the streets, his luck changes when scam artist Harvey Boarden (Terrence Howard) sees that he has a natural talent for streetfighting. When Harvey offers Shawn help at making the real cash, the two form an uneasy partnership.

As Shawn's manager, Harvey introduces him to the corrupt bare-knuckle circuit, where rich men bet on disposable pawns. Almost overnight, he becomes a star brawler, taking down professional boxers, mixed martial arts champs and ultimate fighters in a series of staggeringly intense bouts. But if Shawn ever hopes to escape the dark world in which he's found himself, he must now face the toughest fight of his life.