Story of Maximum revolves around two of Mumbai Police's top encounter specialists. It's a story of their fight for control and one-upmanship. This fight goes through a complex maze of politics, land deals, fake encounters and bad money. Pundit (Sonu Sood) and Inamdar (Naseeruddin Shah) are two encounter specialists who try to overtake each other for power. Each kill the other's informers and the Mumbai police gets divided. Inamdar and his superiors frame a false case against Pundit and he gets suspended. After a couple of years Pundit comes back into the force with the help of a minister, Tiwari (Vinay Pathak). After the Mumbai blasts Inamdar is removed from his position and Pundit gets reinstated. Meanwhile, it is time for the elections and Tiwari gets the responsibility of the entire procedure. One night when he is at home his accomplices are shot. He goes forward to check and finds the culprit to be Pundit. Before Tiwari can shoot him Pundit shoots Pathak.

In flashback, it is shown that while Pundit is travelling with his wife, Supriya (Neha Dhupia) there are shots of the car. In the confusion his car falls into a jungle. After that he shoots all the people and says that they were Niranjan's people. But when he comes back, he realises that his wife is no more. Then it is revealed that Tiwari had got an offer of Home Ministry and 700 million from Pundit's enemies in exchange of Pundit and thus had sent his men to attack Pundit and ended up killing his wife. That was the reason Pundit shot Tiwari.

Before dying Tiwari confesses that he should not have done what he did. He said he should have rejected, but could not reject the offer of Home Ministry. He says that if you have always wanted something throughout your life and then that comes in front of you then a man cannot resist. Pundit asks whether Subodh(his superior) knew of this. Finally Pundit shoots Tiwari.

Pundit hands over property documents to a reporter. The reporter tells him that there's no going back once this goes public. Pundit says that he does not want to return. Pundit comes with his daughter and the reporter to leave the city. Meanwhile Inamdar with his men starts shooting at them. Many people from both sides are shot dead in the shootout. Meanwhile the train is about to start. Pundit sends off his daughter with his brother and the reporter to catch the train. She is unwilling to leave without him, but finally leaves teary eyed. An open shootout follows in which both Pundit and Inamdar are shot. A severely injured Pundit runs towards the train to meet his daughter. Before he can do so he is shot by Inamdar. Yet before dying,l he manages to shoot Inamdar. Pundit has a last look at his daughter before finally dropping dead.