Paap Ki Duniya is an action romantic drama. The movie follows the story of Jailor Shamsher Singh (Pran), who is shocked to learn that his sister is in love with a notorious criminal Pasha (Danny Denzongpa). He rejects the match, but his sister, who is blinded with love, leaves her brother and moves out with Pasha. Sometime later, Shamsher’s sister returns bruised and with an infant, and reveals that Pasha only married her to manipulate Shamsher to free him of all charges, and dies in his arms. Pasha then kidnaps Shamsher’s son Ashok (Sunny Deol), renames him Suraj and raises him as a criminal, while Shamsher raises Pasha’s son Vijay (Chunky Pandey) and makes him inspector. Pasha, still hungry for revenge, decides to teach Shamsher a lesson, by turning his own son against him. Will Shamsher finally succeed in making things right for everyone?