A chance encounter of the unassuming bank receptionist Harleen Sahni (Katrina Kaif) with the charming yet mysterious Rajveer Nanda (Hrithik Roshan), results in an on-rush of ditched planes, car chases, shoot-outs, bombing raids and general global mayhem. But as the transcontinental chase ensues with Rajveer convincing Harleen that he's the good guy, can she really trust him, and will trust matter when the bullets start flying? Fox Star Studios and Director Siddharth Anand promise edge of the seat excitement and adrenaline-pumping action as the duo fight against all odds. Expect explosions, trigger happy assassins and pandemonium that can only aptly be termed as Bang Bang!