Deewane, Vishal (Ajay Devgan) is a hard-working, diligent, and honest plain-clothes police officer in Bombay, India. He lives with his mom (Reema Lagoo) and sister (Usha Bachani). He is in love with Sapna (Urmilla Matondkar). Sapna lives with her family, mom Dhanwanti (Padmini Kapila), dad (Tiku Talsania), and a sister, Neemo (Neha P.). Sapna also loves Vishal, but frequently gets upset with him when he finds no time for her during to his police duties. One day during an encounter, Vishal is critically injured and lapses into a deep coma. In order to prevent the criminal elements to think that they have an upper hand, the Commissioner of Police recruits a con man, Arun (Ajay Devgan), a look-alike of Vishal, and his girlfriend, Pooja (Mahima Choudhary), to take over vishal's place. No one in Vishal's family, nor in Sapna's family is aware of this switch. Arun has not only to fool everyone, but also has to be credible. He is enchanted by Sapna and starts falling in love with her. He is different from Vishal, and is very attentive to Sapna. Sapna appreciates this change in the person she thinks is Vishal, and loves him all the more. Then Vishal's condition improves, and he is ready to leave the hospital and resume his duties and his persona life. But will Arun let go the easy life and the lovely Sapna. And how will Sapna feel when she finds out that her feelings were being played with? Will the criminal elements, including Vishal's own family members, let him re-enter their lives?