The film starts with Aarush (Akshay Kumar), who is seen leaving his job to stay with his friend, Bob (Ritesh Deshmukh) and his wife, Hetal (Lara Dutta). Aarush is jinxed, everything he does is turned upon him, in fact, even his job is unlucky for him. Desperate to get lucky, Aarush decides to go to a priest, who tells him that his luck will turn once he gets married. Therefore, Bob and Hetal decide to get him married to their boss' daughter, Devika Samtani (Jiah Khan). On their honeymoon in Italy, Devika leaves him for her actual American boyfriend, and due to that, Aarush decides to commit suicide by trying to drown under the sea, until he is saved by Soundarya Bhagyalakshmi Venkateshwari Baassappa Rao, aka Sandy (Deepika Padukone).
Him and Sandy both fall in love at first sight, and decide to get married (Sandy not knowing about Aarush and Devika). Once Sandy finds out he is already married, they break-up, but when they get divorced, Sandy comes back to Aarush, and the two decide to go back to London. The two stay with Bob and Hetal, who all get big problems on their hand, and all decide to create their own lies to save their butts.
For Hetal, she has consistently told that she's married to a rich boy and living it up in a big mansion, doing so to impress her dad (Boman Irani), who has frowned upon her decision to stay in London with Bob. For Sandy, her lie involves something similar to her brother. When her brother plans to come and meet Aarush, they all think of a plan to fool him and try to make him look lucky. Her brother turns out to be army officer Major Krishna Rao (Arjun Rampal) who does not approve of Aarush.