Rahul Malhotra (Aamir Khan) is the Caretaker of a garment company that has a pending order of two lakh shirts to Mr Bijlani. Rahul is also the guardian of his deceased sister's mischievous kids: Sunny, Munni, and Vicky. He finds it hard to control the kids, as he is new to this. When the kids cause trouble, Rahul punishes them by locking them in their room. However, the children escape and head for a carnival in town.

Vaiyjanti (Juhi Chawla) is the bubbly daughter of a South-Indian Businessman nad music-lover. Her father wants her to get married to natarajan an Iyer-clan music legend, who is somewhat creepy in nature. Viyjanti refuses to marry him and rebels. As punishment, she is also locked up but escapes. She meets the three kids at the carnival and they become friends. Vaiyjanti explains that she has no home as of now so the children, who have taken a liking to her, invite her to stay with them.

The children go to great lengths to hide Vyjanti from Rahul. In a row of hilarious sequences, they are always one step ahead of Rahul before he can discover Vyjanti. Two nights later however, Vyjanti is revealed. Initially angry at first, Rahul sees that the children love her so he gives her a job as the children's governess. Vyjanti begins to live with Rahul and the kids and slowly falls in love with Rahul.

Maya, a seductive, glitzy woman obsessed with Rahul, turns out to be Bijlani's daughter. She asks her father to ask for Rahul's hand in marriage. Rahul approves, deciding that it would benefit the children. When Vyjanti and the children find out, Vyjanti is heartbroken and the kids are upset, as they dislike Maya. As the engagement takes place, Vyjanti explains to the kids that she loves Rahul and wants to marry him. The kids come up with a plan to stop the engagement. They crash the party with a dramatic act, which successfully postpones the engagement, but angers Rahul. Back home, he scolds Vyjanti and she admits that she loves him, shocking Rahul.

The next morning, Bijlani comes with Maya to offer Rahul a second chance. Rahul defends Vjyanti against their insults, thereby expressing his own love for her. The mischievous kids bring Egg and rotten Tomatos and throw it at Bijlani and Maya until they run out of the house. Bijlani and Maya set on auctioning Rahul's house as revenge. Rahul asks his workers to work overtime to make up for the shirt orders, which the supportive workers agree to. A successful two lakh shirts are made and loaded onto the delivery truck to be delivered to Bijlani. Bijlani hires some thugs to sabotage the delivery so that it doesn't arrive on time--his cruel plan to ruin Rahul. Much to their distaste, Rahul is able to arrive on time with the order. Just before Bijlani and Maya are arrested, the kids, Vyjanti, Rahul and all the others supporting them, throw eggs at Bijlani, Maya and the other personnel at the auction.

Vyjanti is reunited with her father but he disapproves of getting her married to anyone not from the Iyer clan. All the workers from the factory, Rahul's colleagues, and the children request him to allow Rahul and Vyjanti to marry. With so much persistence, he accepts and Vyjanti and Rahul are finally married in a South-Indian style ceremony.