It is a story of the transformation a man. It is a struggle between the sinful activities and the guilty feeling that stems out of realising the sin.John (John Abraham) is an assassin who works for mob boss Captain (Bharat Dhabolkar).
One fateful day, John aims massacring an entire family, as he stares into the eyes of the little girl whose life is slowly ebbing away from her, realization hits John and he decides to quit and start a life sans bloodshed with his wife Shalini (Priyanka Chopra). But as per the Karmic laws of life, John's plan and life's plan are in direct opposition. Captain is facing a major threat from a rival don Yunus (Vishwajeet Pradhan) and after an attack on his life he decides to teach the city a lesson, his plan is so big in scope that it's never been dreamed. Captain wants to kill off the city's top industrialist, top film producer, the cop backing Yunus, and lastly Yunus himself.
His strategy: Set a precedent so that every one else falls in line and no one even dreams of becoming another Yunus, and no one in the city dares change sides. But to carry out this plan he needs the help of his ace assassin - John. One man who can make this audacious plan work, but he is one man who has sworn never to pick up his gun again. Captain takes away John's love, his wife away from him and holds her hostage; in return he has to kill the five targets in the next 36 hours.
From this point on, John plots, double crosses and triple crosses everyone, allegiances are formed to be broken, friends turn foes and the body count begins to grow. On John's tail is Mumbai's toughest cop Wagh (Shiney Ahuja). Tormented by nightmares of a failure in his past, he is determined to bring John down when he realises it was John who put a blot on his clean record. In a game of cat and mouse, John tries to fight the forces of nature and cut loose from the masters of puppets.