This gangster thriller highlights the economics behind running an Indian mafia organization. In the opening of the film, Ajay Devgan describes the modus operandi of underworld. He states "Despite whatever anybody says, the truth is, in this world everything is done for profit, so is this business. We don't pay taxes, neither do we keep accounts; For this work is done by inducing fear. Anybody can join us anytime, but can never resign. Whoever breaks our law, is broken by us. Here friendship, respect or honesty, the only real reason behind all these is same thing -- Profit". During murder / extortion scenes following, Ajay Devgan adds "profit happens -- like this, like this or like that".
The story revolves around a young man named Chandu (full name : Chandarkant Nagre) (played by Vivek Oberoi) joining the world of crime in the Mumbai underworld to "make it big" someday. Gradually he learns tricks of the trade and increases the gang's earnings and profits. This leads to his affinity with Malik (played by Ajay Devgan) who is the leader of the gang.
However, both come at loggerheads during the execution of a contract killing. Chandu stops the deliberate vehicle crash and falls from Malik's favor. The contract was from a politician who tries to use Malik's gang to eliminate a front-runner, a contender for Home Minister's post. The assassination (a staged truck-car collision) takes place in-spite of Chandu's emotional misdemeanor since Malik, not relaying on Chandu anymore, takes reins in his own hands and gives direct orders.
The rift between Chandu and Malik widens due to various misunderstandings. The Commissioner of Police, Sreenivasan IPS (Mohanlal) makes use of the rift to bring the mafia under control. Chandu and Malik end up becoming bitter enemies. After Chandu's retaliation of the assassination of his lifelong friend of one of lieutenants Warsi, two factions of Mumbai's once most powerful gang 'Company' went to a full-scale war.
Malik and Chandu kill as many members of each opponent gangs as possible. Sreenivasan, as the police chief of the city of murders due to the war, became criticized greatly, but he and his men knew this war ultimately is shortening the to do list of his department. Big number of button men and lieutenants from both gangs were being killed. The war results in an intense chase sequence shot in Kenya where Malik hires hitmen to kill Chandu.
However Chandu survives, though he is injured severely. Sreenivasan convinces Chandu to come back to Mumbai and fight his war with Malik by helping the police bring the mafia under control.
The film reaches its climax when Chandu kills the politician (the mastermind of the contract killing) within the prison. At the same time, one of Chandu's aides named Koda Singh, who swore revenge to kill who went against his friend Chandu, shoots Malik point blank to death in Hong Kong.
This shows, Chandu and Malik came to a truce but Chandu never withdrew his order to Koda to kill Malik. It's not confirmed that whether Chandu has forgotten to withdraw his orders or deliberately kept that on. But, after the assassination Sreenivasan notified Chandu and Chandu became tremendously shocked at this news. So, possibly Chandu forgot to send a come back call to Koda.
Koda Singh is arrested by Hong Kong Police on that day. The film ends, showing Chandu spending the rest of his life in prison after being persuaded by the Police Commissioner to surrender.