The scene opens up with Chicago city in the year 1990. Iqbal Arun Khan (Jackie Shroff) with his little boy Sahir (Aamir Khan as a child), runs a grand circus called The Great Indian Circus, which is mortgaged at the Western Bank of Chicago. Iqbal attempts hard to save the circus from closing permanently by arranging a special show for the bankers to woo them with the magic tricks. But, the bankers did not get happy with the show and the bank's rule continues. Then, Iqbal Khan finishes his life with a bullet in front of the bankers and his kid Sahir. This incident leaves deep mental scarves on Sahir's mind that compels him to take revenge of his father's shocking death. As a grown up, Sahir pulls up socks as a swift thief and plans to finish the bank by completely destroying it. Armed up with all the high-tech gadgets and efficient plan, Sahir robs the huge cash from the bank. Sahir re-opens the circus with this cash and a vivacious girl called Aaliya (Katrina Kaif) joins him. By the fear of closing down, the bank officials decide to catch the thief and save the bank. For this mission, the Indian ACP Jai Dixit (Abhishek Bachchan) and Inspector Ali Akbar (Uday Chopra) are selected. Their ultimate aim is to catch the crook red-handed, which is not at all easy as this thief does not leave any proof after the robbery and hence, he is totally unknown.
Sahir gets to know about these cops on television and he visits ACP Jai in this matter. Sahir deludes Jai by imparting some wrong information about this unknown thief and asks Jai to meet in the bank for more valuable details. They meet in the bank and Sahir captures the bank system details in his hidden camera. Again, the bank is robbed and the criminal escapes like every time. Through some points, ACP Jai comes to know that the criminal is none other than Sahir himself and without wasting any time, ACP Jai and Inspector Ali arrive in Sahir's circus to arrest him. The further tale has something really special that will surely raise one's eyebrows!