A couple, with twin babies, is exhausted and drowsing, while travelling by their car. Unfortunately, their car crashes and the couple die but the twins survived. As the twins' paternal uncle Kartar Singh (Anil Kapoor) is single and doesn't want to get married, he decides to give one surviving son to his elder sister Jeeto (Ratna Pathak) based in London and the other twin to his brother Baldev Singh (Pavan Malhotra) who is settled in Punjab. Kartar himself enjoys his single, lonely life in London.Years pass and both twins grow up as Karan (Arjun Kapoor), living with his aunt in London and Charan (Arjun Kapoor) who lives with his uncle in Punjab. Karan is a free man with no responsibilities whilst Charan is a simple, sweet man who is having a car showroom in Punjab. Karan has a girlfriend, Sweety (Ileana D'Cruz) from past 2 years. Unfortunately, one day, Jeeto is in the same mall as Sweety. Sweety laughs and at the same time when Karan's aunt, Jeeto falls near the escalator. Jeeto misunderstands that Sweety was laughing at her. They have a big quarrel with each other including Jeeto accusing her as a 'bad girl'.Meanwhile in Punjab, Charan has also a girlfriend, Nafisa (Neha Sharma) who is a Muslim and studying law. So, trouble starts as Baldev decides to marry Charan with a girl from the Punjabi community. Jeeto has her husband's friend Akalpreet Sandhu (Rahul Dev) in mind for Karan, who is willing to marry their daughter Binkle (Athiya Shetty) with a good man. Karan is in Punjab when he gets to know that Jeeto wants him to marry Binkle. So Karan convinces Baldev to propose Charan instead for the wedding proposal with Sandhu. Baldev agrees and convinces Jeeto. So, Baldev takes Charan to London where Kartar welcomes them. Kartar first takes them to his 'Mini Punjab' residence and then to Jeeto's. While in Punjab, Sweety comes with Karan too as her father also lives there. In London, Charan tells his uncle Kartar that he doesn't want to marry Binkle as he is in love with Nafisa. Kartar decides to help him with his creative ideas. Kartar suggests Charan to act as an addict in front of Sandhu family so that they will refuse themselves. Next day, Charan sees Binkle, and he falls in love with her. Binkle takes Charan on a house visit while Kartar drops hints of Charan's substance addiction in Binkle's brother Manpreet (Karan Kundra) ears.Charan tries to tell Kartar about his sudden feelings but falls off the window due to mobile signal problems. Due to this incident, Manpreet confirms Charan's substance addiction to which Baldev opposes and misbehaves. Jeeto and her husband instead of defending Baldev, persuade him to apologize Mr. Sandhu for his misbehavior but Baldev refuses to do so as he thinks it is against his ego. They return home and blame Baldev for their disrespect in front of the rich Mr. Sandhu and also offend Baldev for his poor past. Baldev decides to return to Punjab. He challenges Jeeto that he will marry his Charan at exact 25th of December with a girl much better than Binkle. They end their relationship.Meanwhile, Charan asks Karan to bring Nafisa to the airport so that he could talk about his feelings for her with Baldev. When they land in Punjab, Karan does what Charan asked and confronts them with Nafisa, but coward Charan doesn't dare to speak. Baldev misunderstands that Nafisa is Karan's girlfriend. This creates problems for Karan. By chance, Baldev overhears Sweety's father pleading for her daughter's marriage in Gurudwara. So, Baldev takes Charan's proposal for Sweety who misunderstands her bond getting tied with Karan but later realizes it's tied with Charan. She gets upset and demands that Karan does something about this. While back at London, Jeeto takes proposal of her own Karan to Sandhu to which he agrees. They fix their marriage on 25th December too.Kartar is split between Jeeto and Baldev's marriage events at the same date. To solve his problem, he suggests Baldev to have a destination marriage in London. Baldev agrees and everyone flies to London. Kartar accommodates Sweety and her father in a five-star hotel, and Charan and Baldev in front of Jeeto's residence. Charan decides to tell Binkle that Karan is marrying her without his consent. Both families along with their in-laws gather in a mall for shopping. Charan takes advantage of this and reveals Karan and Sweety's relationship and Binkle is heartbroken, saying that maybe she lacks something as she is refused by every man. Charan feels sorry for her and falls for her more because of her innocence towards him.Charan refuses to fight for his rights on which Karan invites Nafisa to London, increasing Charan's problems. Karan, Charan, Sweety and Nafisa decide to run with their love. But their plan fails when in the next morning Manpreet falls for Nafisa and Sandhu insists her to live at his residence. Nafisa and Manpreet falls for each other. Nafisa starts ignoring Charan. Charan wants to reveal his feelings for Binkle but now, Nafisa appears and confess her love for Manpreet and leaves. So now, Charan is fully for Binkle. Charan and Karan's marriages are planned at the same Gurudwara as the date. Beforehand, Charan and Sweety's engagement is held which Jeeto attends alone from her side. Later, Karan and Binkle's engagement is held which Baldev's family attends sans BaldevBefore Binkle's engagement, Charan confesses all the mishaps and misunderstandings and that he is not drug addict too. He also reveals his feelings to Binkle at last. Kartar dreams of his brother, the twins' father realizing him that he left his children to him and he is ruining their life. After Binkle's engagement, Karan, Sweety, Charan, Binkle, Manpreet, Nafisa and Kartar gather at a place where Kartar declines them to help them and they would have to marry the ones chosen by their parents instead of eloping. So, 25th December arrives when Karan and Charan exchange their Sherwanis, disguising each other. At the Gurudwara, Sweety reveals her love for Karan in front of everyone on which everyone including Charan and Karan shocks because of their exchanged identities. Not to cause more trouble and confusion, they both take Kartar in confidential meeting revealing their exchanged identities where Kartar orders them to wear their original identities and never ever discuss this mishap with their wives. So, their families no more oppose their choices and Karan weds Sweety while Charan weds Binkle.