Shamsher Singh (Dilip Kumar), his son Pratap Singh (Suresh Oberoi), and daughter-in-law lead a happy life in an Indian village. Shamsher works as an engine driver with his friend Gurbaksh Singh (Shammi Kapoor). Pratap is appointed as the new inspector-in-charge of the village but is killed brutally by Jagawar Chaudhary (Amrish Puri), a notorious local smuggler, after Pratap refuses to help Jagawar in his illegal activities. Seeing his son dead, Shamsher Singh is enraged and he kills some of Jagawar's goons whom he had seen throwing his son's dead body in the forest. When he is about to inquire from one of Jagawar's men about the person behind his son's murder, he is stopped by the police and is asked to surrender; Shamsher somehow manages to escape. His daughter-in-law dies while giving birth to Kunal Singh (Sanjay Dutt).
Shamsher takes his grandson Kunal and leaves his village to hide from the police. In the hope of making quick money, to secure his grandson's future, Shamsher starts working for Sir Mizya (Shreeram Lagoo), a powerful underworld don, and takes on a new identity as Sir Shobraj. Over the course of time, he becomes a wealthy and powerful smuggler and the chairman of the Mizya Group.
Meanwhile, Kunal grows up under the strict supervision of Shamsher's loyal employee Abu Baba (Sanjeev Kumar). He falls in love with Durga (Padmini Kolhapure), a beautiful slum girl and the daughter of one of Shamsher's old employee Ganpat. However, things take an ugly turn when Shamsher Singh disagrees to let Kunal marry Durga because of her being from a poor background; he instead warns Durga's mother (Sudha Shivpuri) to leave the city with her daughter or else face serious consequences.
Although Durga is unwilling to leave at first, she later agrees to sacrifice her love and leaves with her mother in a ship to Goa where Shamsher's men try to rape her. Abu Baba comes to their rescue and saves them but is killed by Shamsher's men with the help of Jagawar, who has become a powerful smuggler of Goa. Kunal is devastated after seeing Abu Baba's dead body and promises to take revenge. His investigations into Abu Baba's death eventually lead to the true identity of his grandfather and about his father's killers.