After finishing his shift at a steel mill in North Braddock, Pennsylvania, Russell Baze (played by Christian Bale) comes across his brother Rodney (portrayed by Casey Affleck) at a horse racing simulcast. There, Rodney reveals that he has taken a loan from John Petty (played by Willem Dafoe) to place his bets, as Petty runs a bar and engages in various illegal activities. Determined to help his brother, Russell pays off part of Rodney's debt to Petty, promising to settle the rest with his upcoming paycheck, provided Rodney doesn't manage to pay it off first.
However, tragedy strikes when Russell, under the influence of alcohol, causes a fatal car accident that claims the lives of the occupants, including a young boy. He is subsequently sentenced to prison for vehicular manslaughter. While incarcerated, he receives the heartbreaking news of his father’s passing and learns that his girlfriend Lena (played by Zoe Saldana) has moved on with the local police chief, Wesley Barnes (portrayed by Forest Whitaker).
Upon his release, Russell returns to the mill but finds that his brother is involved in the underground world of bare-knuckle fighting. Rodney, a battle-scarred veteran from four tours in Iraq, is determined to overcome his pride and debts through brute strength. Although ideally Russell would prefer his brother to work alongside him at the mill, Rodney insists that the “nickel and dime” fights won’t suffice for repayment and pushes Petty for something more profitable. Reluctantly, Petty organizes a dangerous match with Harlan DeGroat (played by Woody Harrelson), a volatile drug dealer to whom he owes significant money.
As Russell desperately desires reconcilliation with Lena, he is faced with the reality that she’s expecting Wesley's child, which damps his hopes of a reunion. The stakes rise as Rodney is coerced into losing the match in New Jersey. During the fight, after a fleeting moment of triumph, Rodney sacrifices himself, ultimately submitting to ensure that DeGroat receives the victory. Tragically, this decision leads to dire consequences after the match.
Following a brutal ambush orchestrated by DeGroat, both Petty and Rodney are murdered. In an ironic twist, Petty’s phone inadvertently connects to his bartender Dan's voicemail, leaving behind crucial evidence of DeGroat's guilt. As Russell uncovers the grim truth surrounding his brother's fate, urging from Wesley about Rodney's disappearance pushes him and his uncle Red (portrayed by Sam Shepard) on a quest for answers.
When Russell tracks down DeGroat, a tense confrontation ensues, culminating in a violent duel. Despite Wesley’s desperate pleas for him to surrender, Russell, fueled by grief and vengeance, resolves to avenge his brother by aiming his hunting rifle, delivering a fatal shot to DeGroat. The film concludes solemnly, depicting Russell seated alone at a table, reflecting on the harrowing events that have transpired, fading to black as the weight of his choices hangs heavy in the air.
