The movie starts with the Amman statue, which was guarding the village against evil spirits and negative energy, being moved into an underground room during the temple's renovation. At a graveyard somewhere close to the temple, a group of tantric practitioners capitalise on the Amman being made dormant to awaken evil spirits for black magic purposes. During the ritual, they inadvertently release a demonic entity that they could not contain. The evil spirit then leaves the graveyard in the form of a cloud and moves into the village. The village mendicant-holy man notices the evil spirit and chases after it, but could not prevent it from entering the titular palace. Being mute, his pleadings to warn the palace owner (Radha Ravi) is ignored. Later that night, the spirit attacks the owner who then falls and goes into a coma. His elder son Ramesh (Subbu Panchu), arrives with his wife Sandhya (Vinodhini Vaidyanathan) and their son Suresh (Nithin Manivannann). Together with them are his younger brother, Murali (Siddharth) and his fiancée Anitha (Trisha). Devadas (Soori) arrives as well, in disguise as his father, Sandhu Bondu Naadimuthu (Soori) who was a doctor and had contact with the landowners.

One night the family driver (Raj Kapoor) is killed. after a few nights, Suresh does crazy things and says that someone is telling him to do so. Also Murali sees his father being elevated above the bed and gets scared. Anitha who also sees these things decides to call her brother, Ravi (Sundar C.). One night Ravi sees Suresh drowning and rescues him. He initially suspects Manju (Poonam Bajwa), who was hired by the family as a nurse for Murali's father, but he soon realizes it is not her since she has a different agenda. After that he sets up cameras around the house. A couple of nights later the elder brother goes missing and Ravi sees it. With the cameras, he is able to identify the spirit that is causing havoc. Murali identifies her as Maya (Hansika Motwani), his younger sister.

Maya was loved by all, especially by her father and Murali. She was also the owner of Maya Granites shown in the song Maya Maya. On the day before her marriage, she eloped with one of the workers' son (Vaibhav) and the whole family was shocked and felt disgraced. Three years later in Bangalore, when Murali sees that she is pregnant, he passes the good news to his father and brother as they arrive at their house. Their father asks Maya to come back home to which she agrees. On the day she was supposed to arrive, Maya didn't show up, and Murali thought she had changed her mind. Later Ravi tells that it's not true. Maya and her husband got off a stop earlier since her elder brother wanted them to arrive home safely. While travelling in a Jeep on the way to their palace, Maya's husband was stabbed by the driver. After that, he instructed Maya to go into hiding. But this plan failed when Maya's father arrived and told her to drink poison since she disgraced her family's name and status by marrying someone who belonged to a lower caste. Maya agrees to her father's words with a condition that her husband's life should be spared. After she drank the poison, Maya's elder brother killed her husband in front of her which made Maya vow that she will end the male generation in her family before her father chokes her to death. Ravi also tells that her primary target is Murali since he told their father and elder brother about her whereabouts and also Suresh. Manju tells that her uncle is a priest and lives near the Kerala border.

Ravi goes with Manju to the priest whose disciples at first refused to offer a helping hand because the priest is just recuperating from myocardial infarction (heart attack). But before they leave, the priest decides to help them and starts the pooja. After a few moments, the priest informs that Maya has possessed someone in the palace and it is revealed to be Anitha. It is also shown that Anitha killed Murali's elder brother and also poisons her father-in-law as an act of revenge, even though he managed to recover from his coma. Ravi decides to find Maya's corpse, while Murali, Suresh, and Manju try to distract Anitha by taking the entire family to a restaurant. Their main goal is to get Anitha's blood and put some holy ink on her hair. They manage to get her blood when she is cutting an apple, and one of the assistants (Manobala) manages to put the ink before getting thrashed by Anitha/Maya. There Anitha goes to the house and tries to kill Murali and Suresh. However, it fails and the priest manages to get Maya out of Anitha. Later Ravi and the priest decide to kill the spirit and the only way is to be possessed by the spirit and stab its own corpse. Ravi manages to do it and completes it but the priest gets chest pain and he tells Murali that their only hope is to go to the Amman Pooja that is happening in their village temple as Amman is their final hope. Murali and Suresh get there with Ravi possessed by Maya trying to stop them. When Ravi is about to kill Murali, Amman uses her powers and prevents Maya's spirit from killing Murali and Suresh. Before she leaves, she sees her brother Murali who sheds tears for what had happened to his beloved sister. Before Maya disappears she smiles at Amman. After this incident, Murali, Suresh and Anitha reunite and Ravi reunites with Manju leaving the Aranmanai in the hands of the caretakers. As everyone leaves the palace, Maya's spirit enters a doll and returns to the palace waiting for the right time to swing back into action. The movie ends with a hint of a sequel.