Kia (Kareena Kapoor) is a feminist and highly motivated and driven career woman. She aims to become successful in the business world, and also misleads for more women to become career-minded, instead of just accepting the traditional fate of a housewife. Kabir (Arjun Kapoor) is the son of a successful building constructor (Rajit Kapoor), and has no real aspirations to hold a day job or be permanently employed. He wishes to be a 'house-husband', having been influenced by the happy life that his mother lived as a housewife. While on a flight to Delhi from Chandigarh, the pair meet and become friends. They begin to spend more time together and learn more about each others lifestyle. Kia discovers that Kabir's preference to stay at home fits perfectly with her wish to climb up the corporate ladder. Kia also learns that Kabir has no interest in his fathers business and does not want to inherit his wealth.
Kia and Kabir gradually fall in love and decide to marry, establishing a relationship where Kabir handles the household while Kia is the main breadwinner. The couple live happily together and Kia's career grows as she is offered a generous promotion. After some time, the apartment that they rent is put up for sale. Not wanting to move out, Kabir decides to buy the house, and in order to make payments, he becomes a gym instructor.
During an interview, Kia mentions her 'unusual' marriage and her husband's role in their household. The interviewer is impressed by this, and requests a meeting with Kabir. While being questioned, Kabir explains that it does not matter if ki (feminine) takes up the role of ka (masculine), and ka takes up the role of ki. The interview is a great success and Kabir is asked to hold many more seminars and speeches on Gender Equality and modern marriages. Kabir's busy schedule causes him to stay away from home for much of the day, causing Kia to become upset. She is frustrated at all the attention her husband is receiving and, in order to cover up her jealousy, she accuses Kabir of using their relationship to get recognition and publicity. The couple argue and Kia asks Kabir to stop his public appearances.
Kia travels to the US for her job, and Kabir decides to remain behind. At a college reunion, Kabir is pressured by a friend into giving another interview, which is broadcast on TV. Film actress Jaya Bachchan sees this interview, and asks her husband, superstar Amitabh Bachchan to call Kabir and organise a meeting with him. Jaya is highly impressed with the story of both Kabir and Kia. Meanwhile, Kia's mother (Swaroop Sampat) is taken to the hospital after collapsing, causing Kia to rush back to India.
After learning that Kabir gave another interview, Kia becomes angry and the couple argue. Kia accuses Kabir of using her, saying that he used their relationship for his own profit. Kia further condemns Kabir for gaining fame without working, as she feels that her hard work and successful career are going unnoticed. Dejected, Kabir does not defend himself and starts packing to leave for Chandigarh. Kia comes across a gift that Jaya gave to Kabir for his wife, and also a letter written by the actress, in which she congratulates the pair and says that to be a man who maintains a household rather than work is a brave choice, but to be the wife of such a man is an even harder choice. Kia's mother confronts her about her jealousy, and says that it is the reason for the couples many fights. Kia realizes that she has been unfairly tough on Kabir and apologizes to him for her behavior and temperament. The couple reconcile and find a happy compromise. Kabir's father, who has come to appreciate Kia's business acumen and drive, decides to make her the CEO of his company.