Doug Glatt (Seann William Scott) from Massachusetts, feels ostracized from his family, his father (Eugene Levy) and brother both being doctors. One day he attends a minor league hockey game with his friend Pat (Jay Baruchel). Pat taunts the visiting team during a fight and one of their players climbs into the stands. Doug, in defense of his friend, quickly knocks him out, which prompts the rest of the crowd to cheer him on. Soon after, Doug gets a phone call from the coach of his hometown team who offers him a job as an enforcer, a player whose role is to protect his teammates and act as a deterrent by hitting or fighting opposing players who take liberties with his teammates.
Doug Glatt, a slacker who discovers he has a talent for brawling is approached by a minor league hockey coach and invited to join the team as the "muscle." Despite the fact that Glatt can't skate his best friend, Pat, convinces him to give it a shot, and Glatt becomes a hero to the team and their fans, until the league's reigning goon becomes threatened by Glatt's success and decides to even the score.