Raina (Kareena Kapoor) meets Samir (Salman Khan) while at an orphanage. They both talk to each other and it's love at first sight. Samir and Raina get married despite Samir's parents disapproval.
The couple moves to Melbourne where Samir is a very successful stockbroker. Two years later complications arise in their marriage. The couple goes through a tough time when Samir's business starts sinking. While Raina is working at a local restaurant as a waitress, with her friend Neena (Nauheed Cyrusi) who's business is expanding,wants to send all her employees to Fiji for further training. Raina refuses knowing that Samir will say no. While this is going on, Samir consults his friend Sanjay (Dino Morea), who persuades him to go to Singapore to start a new. That night when Samir comes home he orders her to start packing because they are leaving for Singapore.
At the airport, Raina bumps into Aakash (Sohail Khan), who works at the local café at the airport. After saying sorry and going to their respective places, Aakash follows Raina as he feels that it's love at first sight. Finding out she is married, Aakash leaves his Mrs. Khanna story there and starts working again. Samir then hands Raina her passport and tells her that his flight is after one hour while her flight is in two. Confused Raina asks aren't they going together but when she opens her passport she realises that the destination on her boarding card is Delhi and not Singapore. Confused, Raina asks what this is, when Samir says he cannot leave her alone in Melbourne so she must go back to India and stay with his parents. Samir leaves for Singapore, where Sanjay asks if everything is okay with Raina. Raina sinks into the waiting room chair and starts crying.
The announcement for Mrs. Khanna is being announced to get onto her flight. Aakash notices Mrs. Khanna sitting lifelessly and crying in the departure waiting room Aakash tells her that its her last call. She thanks him and then quickly asks if she could borrow his phone and make an urgent call as it would be late if she went to the phone booth. Aakash agrees and lets Raina borrow his phone. Raina then Calls Neena and tells her everything that happened while Aakash is listening intently. Neena, now in Fiji, then gives Raina two options, either she can get on the plane and leave for Delhi or she can stay and experience the life she never had. She quickly thinks about it and realises if she goes back to Delhi she won't have the opportunity to be independent and make her own decisions . She agrees to stay. Raina then calls Samir to tell him she missed her flight and is staying here. Upset, Samir says he is coming back to get her but she refuses and says that come back when your successful and Samir agrees. Soon Aakash and Raina get to know each other in a short period of time with Aakash always referring to her as Mrs.Khanna rather than Raina. Aakash makes Raina realise that being independent is good and remaining suppressed all the time is not a good idea. Aakash helps Raina to get a new place to live, a new job at the airport and a new life as well.
During this time Aakash has fallen in love with Mrs Khanna although she just views the relationship as a good friendship. Soon Raina's work permit expires and she can't get a new permit as she is marked as single. Victor sir, Harsh and Raina's new friend Tia(Mahek Chahal) all tell Raina to apply for a fake marriage with Aakash so she can work. Raina feels like she would be betraying Samir and says no to it right away. Aakash respects her decision and agrees with it too. On New Year's Eve both Aakash and Mrs.Khanna are alone so they decide to spend it together drinking. They both drink until Mrs Khanna is really drunk. Aakash then drops Mrs Khanna home but it would be too dangerous to leave her alone. Aakash plays the music player at Raina's house and a really old song starts playing both Mrs Khanna and Aakash start dancing. Raina then tells Aakash that he is a good guy and she likes him with Aakash replying the same. The next morning, Raina is seen sleeping on her bed while Aakash is sleeping on her bedroom floor. Raina realises that Aakash is not the type to take advantage of her and later agrees for a fake marriage still not knowing Aakash secretly loves her. They send in the papers and wait for the court to send them a date when they can get "married". Soon enough Aakash has madly fallen in love with Raina and Harsh tells Aakash that he should express his feelings to her. Harsh tells Aakash to show that he is the good guy while Samir isn't as he left her all alone with nothing.
Aakash eventually decides to reveal his feelings for her. As he's getting ready to leave with Harsh, an incredibly good looking man (according to Aakash and Harsh) asks for Tia. They ask him who he is, as the man is about to say his name, Neena, who is standing behind Harsh and Aakash suddenly says "Samir?". Harsh and Aakash both shocked look at each other and whispers "Khanna?". Neena tells Raina that Samir is back. Raina then goes to the airport to the gate where they both separated and are united. Then Raina introduces all the people who helped her including Aakash. Samir thanks them all for helping Raina while he was away. Aakash and Harsh send Tia into Raina and Samir's place so they will not sleep together. Samir thinking Tia really needs help agrees to let her stay at their place while he'll bunk with Harsh and Aakash. Harsh and Aakash realise they didn't think the plan through and now are stuck with Mr.Khanna sleeping with them.
On the first night with Mr.Khanna, Samir once again thanks the guys for helping Raina and then gives them an inspirational bed time story where Raina accidentally threw a tissue paper on the ground and the guy who cleans the area said Oye Miss pick that up and throw it in the garbage. Raina is so impressed she started talking to him and Raina is a type of person who is so sweet anyone misunderstands that she's in love with them but really she just wants to be their friend. Then Samir asks what they do, Aakash says that they are bartenders and then Samir asks that they should drink together sometime but he asks them what they do after work Harsh quickly says they clean tables and realise that the story was intended towards them. Both of them insulted say good night and fall asleep. Harsh then says that we need to find a hot girl to seduce Samir that will make Raina question his character. Both Aakash and Harsh then go to Haseena Jagmagia (Preity Zinta) to get her to seduce Samir and She agrees. Aakash and Harsh take Samir to a bar where Haseena Jagmagia is dancing. They try and succeed at getting Samir drunk. Aakash and Harsh are just waiting on Tia to bring Raina to see what Samir is doing. However, after dancing with Haseena for a while Samir returns to the bar and when Raina walks in she sees Harsh and Aakash dancing with Haseena. Harsh's plan has failed as now Aakash and Harsh's character has come into questioning.
Soon Samir moves back in with Raina and Harsh and Aakash are running out of plans. Samir and Raina go out to dinner and Raina asks for champagne while Samir says that they already have wine why would we need champagne as champagne is for celebration. Samir holds Raina's hand and asks her what she wants she says nothing except for his company and she pauses for a bit. Then she says I want a little Samir, hinting she wants to start a family. Samir is happy and asks for 4 bottles of champagne. Back at Aakash's place, Aakash has received the court papers for Raina and his marriage date. Raina and Samir return home with Samir being really romantic as they are both in the mood for sex. Raina goes to freshen up.
As Samir is going inside he realizes there is a package for Raina. Samir then opens the package and it's the court papers. Samir then asks her who Aakash really is . Raina saying that he's a really good friend and how he's helped her through so much. Samir then pulls out the court papers. Raina then tells him that it was only for the work permit so she could work. Samir says that she could have told him before hand and he could have gotten her the work permit. Now a confident Raina talks back and says just like the way you left me to go to Singapore. Angered Samir now gives Raina the option of her coming to Singapore back with him or get divorced so she can get married to Aakash. Again at a crossroads Raina doesn't know what to do.
Raina asks Aakash if he loves her. Aakash tells her that she is so pretty that anyone can fall in love with you Mrs. Khanna. Samir then jokes about Raina checking her boarding ticket that they are both going to the same place. Samir then sends Raina to go to boarding while Aakash stops Samir and says you two were made for each other. He then adds that Mrs. Khanna never let him near her, and at least Samir hugs him. Samir and Aakash are shown on good terms and Samir leaves. Samir and Raina are now on the plane waiting for it to take off while a flight attendant comes in and gives Raina a bouquet of flowers from Mr. Khanna. Raina then thanks Samir for giving her the flowers as they are beautiful. Samir starts laughing admitting that they are beautiful but they are not from him. Raina then realizes there is a card in the bouquet. She opens up the card where its expressing Mr. Khanna's love for Raina. As soon as she reads the name on the card Samir says do you now realize why he use to call you Mrs. Khanna and not Raina? The bouquet was in fact from Aakash who's surname is Khanna and he would pretend that Raina was his wife referring to her as Meri(my) Mrs. Khanna. Raina then smiles and now leaving Melbourne to start her life afresh with Samir.
Aakash is still thinking about Mrs. Khanna, while a young beautiful girl (Deepika Padukone) appears and asks if they are open. Harsh quickly says yes and starts up coffee. Harsh then hints to Aakash to try his luck with her. Aakash then asks the young girl what's her name. She replies saying Mrs.Khan. Aakash and Harsh are shocked and then Aakash get the idea of getting into trouble with another Mrs. But then quickly the girl says that she wanted to be Mrs.Khan but it didn't happen. Happy Aakash then tries his luck as she asks his name. Harsh then says his name is Mr. Khan. Confused Aakash adds the "-na" to Khan. Then asks if she's looking to get married. The confused girl then says good-bye and is about to leave when Harsh indicates for Aakash to start singing the song that he and Mrs. Khanna danced to on New Years. The girl then stops, looks back and smiles. Afterwards it is seen that the girl and Aakash are sitting together talking. Aakash asks the girl what her name is and she simply replies by saying her name is Raina. Aakash starts laughing and then jokingly asks if the Mr.Khan guy she was supposed to get married to name was named Samir and she replies yes how did you know? The movie ends here as Aakash is shocked because of the coincidence.
