Jyoti Thakur (Hema Malini) is a famous and honest advocate. Along with DCP Khanna (Rajesh Khanna), she launches a tirade against a Minister Prajapati (Anupam Kher), Shakaal and Vicky, who perpetrate terror in the city. Khanna cracks up a smuggling operation and sends Shakaal and Vicky to prison, but Prajapati uses his influence in the executive and procures their release. The Minister is aided in his criminal activities by a corrupt police officer Makkad (Tej Sapru).
Prajapati tries to influence Jyoti by bribing her, but she spurns the offer. He then tries to exterminate Jyoti, but is saved by Inspector Arjun (Govinda), who is in love with Nisha (Madhuri Dixit), when they ware together in Missourie—Nisha for higher studies and Arjun for police training. Nisha is none other than Jyoti's sister.
When all attempts to influence Jyoti and Khanna fail, Prajapati gets Khanna murdered and in a frustrated move, also gets Nisha gang-raped.
Due to a loophole in law, the criminals are acquitted and Jyoti now throws her lawyer's mantle and prepares herself to wreak vengeance.
Does Jyoti succeed in her plans and what was her strategy? How does Arjun avenge the murder of his Godfather, DCP Khanna? What happens to Nisha after she is gang-raped?
Does the Minister Prajapati get exposed, or does he carry on with his evil activity?
The answers for all these, are unfolded in a breath-taking climax of 'Paap Ka Ant'.
(From the official press booklet)