Jai leaves behind his pregnant wife Lekha in a town to search for her parents in Sri Lanka. He is wounded during an attack when he tries to save fellow Tamil people, Raj, Ajith, Mani, and Shiva, who later become his best friends after he saves them from a certain death.
Meanwhile, at home, Lekha endures a painful pregnancy alone. She calls out for help but is too weak to be heard. Rumors swirl through the village that Lekha died in labor and has returned as a powerful ghost haunting the house. The neighbors report hearing lullabies near the baby, a chilling sound that terrifies them into silence.
When Jai and his friends return to town in the evening, they find the streets eerily quiet. The five soon arrive at Jai and Lekha's house during the night, and Jai introduces Lekha to the group. With night falling, the friends decide to stay rather than press on.
The following day, the men visit the village market but are met with fear and suspicion from the locals. A drunk villager tries to warn Jai but is hushed by his own son. The group discusses what they have heard, but Ajith—sent to fetch Jai—witnesses troubling signs: a dilapidated house that hasn’t seen maintenance in months, a baby cot rocking by itself, and Lekha extending her arm to retrieve a dropped apple from under the house. The next day, Mani discovers a decomposed corpse behind the house wearing the same ring as Lekha, and the drunk villager who had warned them earlier is found drowned. Soon, the friends are convinced that Lekha is a ghost.
They try to prove their case through games and tests, including a tense round of charades, but Lekha nearly harms them, and only Jai’s presence stops her. Frustrated and afraid, Jai tells them they are no longer welcome in his life and orders them out of their accommodations.
Later, Jai and Lekha go on a date to a town amusement park. The friends attempt to pull Jai away by kidnapping him, but Lekha intervenes and chases them off. During the escape, Jai’s wound reopens. The friends are astonished by the amount of blood, and Ajith and Mani grow convinced that Jai is the ghost, especially when he reacts to the holy rice. They flee, rescuing Lekha in the process. While rowing away, Jai appears to return to his friends, walking into the river, but cramps nearly cause him to drown. Since ghosts aren’t supposed to feel cramps, Jai is revealed to be alive, and he explains that the pain came from his wound and the rice.
In the confusion, Raj drops a ring identical to the one the group had seen on the corpse behind the house. Raj is immediately accused of being a ghost and is cast off the boat. The others, now without paddles, drift farther from shore. Lekha conjures a soaking wet paddle for Mani, who recalls that all of them had been thrown overboard and drifted far out. Mani stands and looks between his legs, and Lekha’s true nature is revealed: she is the ghost. The remaining four men, including Jai, retreat to a temple for protection.
Inside the temple, the four are guarded by a local monk, who wields holy rice and water, and a protective “safety ring” around the sacred space. Lekha arrives in a terrifying ghostly form and attacks. The holy weapons initially hold her at bay, but panic and Jai’s struggle to return to his wife cause the ring to fail; the monk is forced to flee, and the group finds themselves stranded as the “safety ring” is destroyed. A pale Raj reappears, and it’s revealed that he is human after all; he had stolen the ring from the corpse behind the house to finance gambling.
Lekha declares she only wanted to be with her loved one, while the others insist that the living cannot be with the dead. She denies killing the drunk and suggests the man’s death was his own doing. She threatens Jai but stops when she sees how frightened she’s made him.
Jai reveals that he always suspected the truth. He had glimpsed Lekha’s ghostly form and found her decomposed body, but he chooses to stay with her rather than live without her. The couple reconciles, and his friends tearfully reaffirm their friendship, vowing never to abandon one another again. A flashback to Jai and Lekha’s first meeting punctuates their renewed bond.
In the end credits, Jai, Lekha, and their four friends live peacefully in the village. Lekha uses her supernatural abilities to help with chores, play charades (aided by Mak’s win for the first time), deter villagers who seek to drive her away (led by the village drunk’s son), and even run the town’s haunted-house attraction. It is revealed that her child also inherits some of her abilities, though he is still an infant.
