In the Bronx during the 1940s, an Italian-American middleweight boxer known for his violent temper and powerful fists fights his way through the ranks of the boxing world. Fueled by rage and the desire to be the best, his fierce style and haymaker punches earn him a reputation in the ring, as well as a shot at the championship. But his brutal nature is not confined to the boxing arena; it spills into his personal life, where his obsessive jealousy and uncontrollable anger damage his relationships with his brother and his wife. The boxer's inability to express his emotions manifests in self-destructive behavior and physical confrontations outside the ring.

As his career progresses, the boxer faces a series of professional highs and lows, which mirror the turbulent ups and downs of his personal life. Despite his success in the ring, his paranoia and distrust sour his relationships, making him increasingly isolated and volatile. His marriage suffers under the strain of his jealousy, leading to abuse and strife. Meanwhile, his ties to his brother and manager become strained due to his suspicions and erratic actions. These internal battles threaten to undermine his boxing career and his personal life, as he struggles with the disparity between his public image as a champion and his private battles with anger and insecurity.