Amar Manohar (Aamir Khan) and Prem Bhopali (Salman Khan) are two ne'er-do-wells from Bhopal who dream of becoming rich without working for it?by marrying a rich heiress, Raveena (Raveena Tandon). One has a habit of saying 'Aai laa!' and the other has a habit of saying 'Ooii Maa!'. They meet on a bus and discover that they are both out to win the heiress. Each of them tries various ploys to eliminate his rival, all of which fail ludicrously. In the end, Amar and Prem agree to join forces, insinuate themselves into the heiress' household, and there compete for Raveena's love.
Amar tries to get Raveena to hit him by annoying her. After several tries, he succeeds when Raveena, quite fed up with him, hits him with a log of wood. Amar acts as if he is unconscious. He is taken into Raveena's mansion, where he is attended by Prem, pretending to be a doctor. After some skirmishing for Raveena's attention, Prem finds himself increasingly attracted to Karisma (Karisma Kapoor), Raveena's secretary. What Amar and Prem do not know is that Karisma?whose actual name is Raveena?is the real heiress. She switched places with her secretary in an attempt to find a man who would love her for herself, not for her money.
Amar and Prem then concoct an inane plot to win the confidence of the heiress's father Ram Gopal Bajaj (Paresh Rawal) by first kidnapping and then rescuing him. But they do not know that the father's evil twin Teja aka Shyam Gopal Bajaj (Paresh Rawal) has plans to kidnap him too, and start living as him. So both Teja and Amar and Prem send their men to kidnap him. But Teja's men take him by rendering the men sent by Amar and Prem unconscious. Amar and Prem then decide that they will really have to rescue him. Later Amar and Prem find out that Raveena was really Karishma and Karishma was Raveena and that they both wanted to experience each other's life because of how they didn't get the respect they wanted.
But Teja himself has an enemy, Crime Master Gogo (Shakti Kapoor), who then enters the plot. He takes everyone hostage, including Raveena, Karishma, Ram Gopal Bajaj, Teja and his cronies Robert (Viju Khote) and Bhalla (Shehzad Khan) to steal the precious diamonds that belong to the rich Ram Gopal Bajaj. Amar and Prem go to rescue them all.