Subhash Nagre (Amitabh Bachchan), who is known by his followers as Sarkar, lives in Mumbai. The opening scenes show a rape victim's father (Veerendra Saxena) approaching Sarkar for justice (which the corrupt law and order system has failed to deliver) which Sarkar promptly establishes by having the rapist beaten up by his henchmen. His son, Vishnu (Kay Kay Menon), plays a sleazy producer who is more interested in the film actress Sapna (Nisha Kothari) than his wife Amrita (Rukhsar). Sarkar's other, more upright son, Shankar (Abhishek Bachchan), returns from the United States with his love Pooja (Katrina Kaif) after completing his education there. Pooja's doubts about Sarkar's image cause Shankar, who firmly believes in his father's righteousness, to break up with her later in the movie.
One day, a Dubai-based don, Rasheed (Zakir Hussain) tries to strike a deal with Sarkar; he promptly refuses on moral grounds and also forbids him from doing it himself. Rasheed tries to eliminate Sarkar's supremacy with the help of Selvar Mani (Kota Srinivasa Rao), Sarkar's former associate, Vishram Bhagat and Swami Virendra (Jeeva). Meanwhile, they trap Sarkar by assassinating a righteous, upright, Ahimsa political leader and an outspoken critic of Sarkar, Motilal Khurana (Anupam Kher). Everyone, including Vishnu believe that Sarkar is guilty but Shankar has deep faith in his father. Sarkar gets arrested. Shankar now takes over the position of Sarkar temporarily. On learning of a plot to murder his father in prison, he approaches the police commissioner (Anant Jog) who mocks him and his father besides not providing protection. By the time he reaches the prison and appropriate action is taken, the attempt on Sarkar's life is already made. Sarkar is later acquitted. He remains bedridden as Shankar takes on Sarkar's enemies.
Meanwhile, Selvar Mani, Swami, Vishram and Rasheed try to convince Vishnu to murder Sarkar. Vishnu was previously thrown out of Sarkar's house because he had murdered the actor who was having an affair with Sapna. Vishnu returns home pretending to have repented. When he approaches Sarkar in the dark of the night with the intent of murdering him, Shankar foils his plan and later kills him (establishing justice by the way of his father). Shankar eliminates Rasheed, Vishram and Selvar Mani. He also succeeds in making Swami his puppet. Shankar has also realised that Chief Minister Madan Rathore (Deepak Shirke) also has a part in the attempt to end Sarkar and his rule. This results in legal action against the Chief Minister. The closing scenes show people approaching Shankar for justice and his father apparently retired.