Samir (Salman Khan) is a very successful doctor: He not only looks after his patient's maladies, he also looks after his female patients' hearts. Most women fall for him and his irresistible charms. The only person who has not fallen for him is his dutiful nurse Naina (Sushmita Sen).

Whenever a girl gets too close to Samir and starts talking about marriage, he sends her off by telling her he is already married. However, one day, he meets Sonia (Katrina Kaif), a beautiful young woman and Samir is smitten. He lies to her about having a wife, but the marriage is failing. When she learns of his 'wife', she wants to meet her. Samir introduces Naina, as well as her niece and nephew, as his wife and children.

Samir then arranges a fake divorce from his fake wife with the help of his best friend, lawyer Vicky (Arshad Warsi) who, despite having a steady girlfriend (Ishaa Koppikar), frequently flirts with Naina. To complicate things further, Samir's mother (Beena Kak) suddenly appears and doesn't want her son get divorced from Naina (when he isn't married to her in the first place). And then, there is Sonia's neighbour Pyare (Sohail Khan), who does not want Sonia to marry Samir: He wants Sonia for his own and she seems to like him, too.

The web of lies around everyone grows thicker and thicker, but finally, Samir is able to persuade Sonia to marry him. But before the altar, she makes him realize that she isn't the right wife for him; he is in love with Naina who has proved her love since she played along, pretending to be his wife. Samir agrees and rushes to the airport, because Naina wants to escape to Canada, while Sonia gets married to Pyare. At the airport, Samir arrives in time: He convinces Naina to stay and she agrees.