Boxer is an action sports drama. The movie follows the story of a young man named Shankar Dharma (Mithun Chakraborty), who does petty thefts and gets jailed for one of them committed by him. In the jail he meets another inmate named Tony, who witnesses his fight with an inmate in jail and impressed by his fighting skills, he introduces Shankar to boxing. Upon his release from the jail, Shankar becomes a professional boxer and embraces the fame. However, will he ever get rid of his haunting past?