The film focuses on the transferred IRS officer Amay Patnaik (Ajay Devgn) to Lucknow as Deputy Commissioner of Income Tax, who lives happily with his wife Malini (Ileana D’Cruz). One day, he receives an anonymous tip about the black money hoarded by (Member of Parliament) Rameshwar Singh, the don of Sitagarh, who has evaded paying the income tax for a very long time. So, Amay and his team plan heavily and head over to Sitagarh. There he faces hostility from Rameshwar’s family but he keeps up his honest attitude. He searches every nook and corner of the house with his team to find black money, but to no avail.
After a few hours, when all hope is lost, he receives an anonymous letter revealing to him the location of the money in the house, along with a map. So, Amay and his team break down the walls, ceilings, staircases and old storerooms (with the help of the map) to find assets worth crores. MP Rameshwar, not willing to accept defeat, goads Amay into letting him leave the house. He meets the then Chief Minister of Uttar Pradesh, but the CM refuses any aid as the IT department is under the Central government’s control and the raid is legal.
The central finance minister is forced to call to Amay, but is rebuffed. A relentless Rameshwar meets several MPs politicians, senior officers and even tries to meet the then Prime Minister, Indira Gandhi herself, but to no avail. He rallies his political support and threatens to topple the state cabinet unless the Prime Minister agrees to meet him. When the raid proceeds for the 3rd night, the PM and Rameshwar meet. PM Indira Gandhi calls Amay, and tells him to look for other legal options. Amay agrees, as long as she provides a signed order through fax to stop the raid, effectively negating the request. The PM is impressed by Amay’s courage, spirit, and intelligence and sends Rameshwar away. Frustrated, Rameshwar tries to attack Malini, which she escapes narrowly. On hearing this, Amay becomes furious but controls his anger.
Finally, on the 4th day at noon, Rameshwar’s henchmen come to kill Amay and his team. After a long struggle, a nearly defeated Amay is saved in time by special police forces sent by the PM. Rameshwar is arrested but upon asking about the identity of Amay’s informer, the latter refuses to disclose it as per the rules. Later, it is revealed that it is Rameshwar’s youngest daughter-in-law was the informer as she and her lover wanted revenge on him for marrying her forcefully to his impotent son. Rameshwar is left wondering about the informer’s identity in prison while Amay gets transferred to some other place, with a hope for a bright future.