Plot

Realizing he is the target of a vengeful family that welcomed him without knowing his identity, a young man must avoid exiting their house since they won't kill a guest unless he's outside.

The story revolves around two families, whose leaders killed each other many years ago. Two sons from the family left, Jaswinder Randhawa (Ajay Devgan) and Balwinder Singh (Sanjay Dutt), are sworn enemies. Jaswinder was hidden in London by his mother (who wanted the feud to end), whereas Balwinder is waiting for his return in Punjab so he can take revenge for the death of his father. Till Balwinder avenged his father's death, he vowed not to marry. His would-be bride Pammi (Juhi Chawla) has been waiting for years for Balwinder to end his vow. Balwinder forces the kids in his house to give up ice cream and soft drinks till the death is avenged.

Now in modern day, Jassi Randhawa (Ajay Devgan) is an unemployed good-for-nothing who receives a letter from the Punjab government about buying his property in Punjab. To finalize and sell the property, Jassi leaves for Punjab. On the train, he meets and falls in love with Sukhmeet (Sonakshi Sinha), who leaves at her station.

In Punjab, Jassi accidentally hurts Billu (Sanjay Dutt) and, seeing he is new to the area, Billu invites Jassi to his home, where he treats Jassi like a god. There, Jassi realizes that Billu is Sukhmeet's brother. Soon enough, it turns out that Billu is Balwinder Singh and realizes that Jassi is short for Jaswinder.

However, Billu's family has one rule: A guest in the house should never be disturbed. Now, Billu must wait for Jassi to leave the house to kill him, but Jassi finds out and comes up with a hilarious plan to foil Billu's shenanigans.

Jassi fakes a back injury when he asked to leave the house & uses that to extend his stay in the household & delay his eventual fight with Billu & his men. The ladies of the house, Pammi, Sukh, Poly & Sweety don't know anything about Jassi being from the Randhawa family.

Jassi calls the police to come and escort him from the house, which the police inspector does. The inspector takes him to an abandoned fort, where Billu and his men are waiting for Jassi. The inspector is Billu's childhood friend. Jassi escapes on a horse & after a protracted chase, re-enters the Sandhu house & re-instates his status as a guest.

Jassi mistakes Sukh's friendship with her childhood friend Bobby as her love for Bobby & is heartbroken. In reality Sukh also loves Jassi, but both are reluctant to admit their love directly to each other. At the festival of Lodhi Billu announces the engagement of Bobby & Sukh. But Bobby announces that he and Sukh are just friends & that he cannot get married to Sukh. He did this because he knew about Sukh's feelings for Jassi. Billu is feeling insulted, but Jassi intervenes & convinces Bobby to agree to the match with Sukh. Bobby agrees thinking that Jassi no longer loves Sukh.

That night Billu tells Jassi that the next day is Sukh's engagement to Bobby & everyone will step out of the house, Including Jassi. So Jassi is done for. The next day Jassi steps out, but Billu orders his men to stop as he does not want bloodshed in Sukh's presence. After Sukh leaves the Sandhu family attacks Jassi, but Jassi fights back. At the Gurudwara, Bobby & Pammi tell Sukh that Jassi is actually the son of the Randhawa family, whom Billu has sworn to kill. Pammi says that Bobby agreed to the engagement only so that Jassi could stay in the house for another day. Pammi knew that Sukh loved Jassi & hence could not allow Jassi to be killed.

Pammi tells Sukh to go and meet Jassi before he leaves town. Pammi also promises to handle Billu. Jassi & Sukh declare their love for each other & defeat the goons. Jassi then takes Sukh to meet Billu as he wants the enmity to die. But instead of the burying the hatchet, Billu attacks Jassi. They fight for a long time & eventually reach the house veranda itself, where Sukh reminds Billu that he can't kill a guest inside the house.

Then Billu's grandmother urges Billu to forgive Jassi as it has been 25 years since the events of the past, which should now be forgotten. Billu finally forgives Jassi & agrees to Jassi' wedding to Sukh. Billu gets married to Pammi.