Gopal (Ajay Devgn), Madhav (Arshad Warsi), Lucky (Tusshar Kapoor), Laxman 1 (Shreyas Talpade) and Laxman 2 (Kunal Khemu) are orphans who stay in an orphanage and are the first ones to stay there. The orphanage is funded and managed by Jamnadas (Uday Tikekar), who is a successful businessman, and is located in Ooty.
Gopal is short-tempered and breaks the fingers of people who point those at him. However, at night, Gopal sleeps in fear of ghost coming to haunt him.This leads to his friendship with Laxman 1. Among the orphans, Jamnadas' favourite is Pappi who tends to forget things. One night, Gopal, Madhav, Lucky and both of the Laxmans find a baby girl at the gate of the orphanage. They name her Khushi. They take care of her till she grows up. The five boys also know Anna as she worked in a library with her father where orphans used to frequently visit. Anna could see spirits and the five boys know about this.
One day while playing cricket, the ball goes into a vacant bungalow belonging to Jamnadas' close friend. Madhav scares Gopal which leads to a fight eventually. Gopal gets punished and hence decides to leave the orphanage with Laxman 1. Madhav, Lucky and Laxman 2 also leave. Jamnadas and Khushi miss them every day. Later, Khushi gets adopted by colonel.
Years later, Gopal and Laxman 1 work for Babli Bhai (Sanjay Mishra). Madhav, Laxman 2 and Lucky work for Vasooli Bhai (Mukesh Tiwari). The trio scares people and makes them leave the house. The five find out that Jamnadas has died and there is a ritual to be held to honour him. They return to the orphanage after 25 years. They find paintings on the walls of the orphanage.
Madhav challenges Gopal to enter the bungalow. The trio, Madhav, Lucky and Laxman 2, run to do their previous prank on Gopal. Laxman 1 also enters the bungalow. All five of them get scared by seeing a girl (Parineeti Chopra). They meet Anna Matthew (Tabu), Colonel and Damini, the bungalow's caretaker. The five return after the ritual. In the meanwhile, Vasu Reddy (Prakash Raj) tell the kids that they will be shifted to another orphanage. Laxman 1 gets possessed and talks in Nana Patekar's voice which scares Gopal. They call Anna; she suggests them to stay in Colonel's house.
Later, Madhav gets possessed and talks to Vasooli when he is sent back to Ooty with his friends to stay and remove the members from a house who turn out to be Gopal and Laxman 1.The five fight daily which causes Gopal to feel something for Damini. Soon they unite after Lucky gets possessed. Madhav, Lucky and Laxmans tell Gopal to express his love to Damini. Pappi enters and tells them that Damini is his girlfriend and alive. They find out that Damini they were introduced to is dead and is the spirit of Khushi, the Colonel's daughter. All of them get scared and try to escape. Pappi and Vasooli come to their rescue but the spirit scares them too.
Anna reveals the truth that the ghost is none other than their own Khushi. Khushi tells her tale. She met Nikhil (Neil Nitin Mukesh) and fall in love with him. Later, she witnessed Nikhil killing Jamnadas. Nikhil strangle Khushi to death. With Vasu Reddy's help, he proves Jamnadas' death as a suicide and Khushi's as an accident. Anna and the five boys plan to make Vasu confess everything about that night with the help of Pandurang (Vrajesh Hirjee). But what they planned was about to be achieved, Nikhil comes back. This infuriates Khushi. Khushi gets justice and happily goes to heaven.