Saravanan Prem, an NRI living in Kuala Lumpur, returns to India after hearing about floods in Wayanad, only to face a painful reality: his parents lie in the hospital mortuary and he breaks down in tears.
In the same ancestral home, a sorrowful quartet of ghosts haunts the place—Meera Tamannaah Bhatia, Vijay Karuppaati, Nivetha, and Santhanam—awaiting the return of Vijay Karuppaati's wife, clueless about when or how they died and what remains of their world here.
A prospective tenant visits the house and the broker Ganapathy is the first to glimpse the supernatural, scared into reporting the haunting to the house owner, Saravanan, and his cop friend Vetri. Vetri grows suspicious, while Saravanan dismisses the tale as a trick of the imagination. The unsettling news quickly catches the attention of Vetri, who teams up with Guru Mime Gopi to pressure Saravanan into selling the property cheaply by spinning a ghostly scare story. Their plan is to demolish the house and replace it with a commercial complex.
Senthil Munishkanth overhears the scheme and agrees to a dangerous bet: he will send his three friends to stay one night in the house, and if they survive, Saravanan will pay Senthil a percentage of the eventual sale price. That night, the four friends—Kaali TSK among them—confront the uncanny presence. Kumar is locked in the bathroom, Muthuswamy is knocked unconscious, and another friend is merely frightened away. The encounter plants a seed of belief in Saravanan that something truly supernatural haunts the home, yet he reluctantly postpones any decision to sell.
Senthil and his companion Tulasi cross paths with Kaali and Raju at the hospital, and all four men are in dire need of money. Senthil himself has to care for his amnesiac mother and is desperate for cash to fund a life-saving cardiac surgery. Meanwhile, a wandering film slicker named Paaripooranam pretends to be an agent of Kollywood producers and dupes Kaali, who is so film-obsessed that he begins performing scenes from movies he admires. The other subplots introduce Thangam, a drunken, compulsive gambler who drinks after the clock strikes 9 p.m. and loses the money saved for his son’s surgery; and Nandha, a deaf, night-blind man who relies on his flute when frightened and who is suddenly drawn into trouble after an ATM security job goes awry.
As the nights unfold, the four friends stay oddly calm, their peculiar habits turning the tables on the spirits. Kaali’s habit of acting out scenes from cinema unsettles the spectral visitors, and the living start to intimidate the ghosts rather than the other way around. After the first day, Saravanan asks Senthil to show a bit more patience and gives him two more days to attempt a sale. Vetri intensifies his pressure, resenting the three friends’ presence and dispatches counterfeit spirits to frighten them away. The real ghosts, however, outwit the phantoms and ghostly impostors alike.
On the second night, the foursome remains composed and manages to scare away the haunting threats. By the third night, a surprising turn occurs: Senthil’s mother arrives at the house, seeking him, and turns out to be the wife of Vijay Karuppaati. The truth comes out in a dramatic flashback: Saravanan is the son of the couple, and years earlier he left for Malaysia after receiving a job offer. The parents end up adopting Meera, Nivetha, and Santhanam after feeling isolated. Saravanan returns, suffers business losses, and resolves to sell the house to cover his debts. A brutal confrontation follows: Vijay Karuppaati refuses to sell and insults Meera and Nivetha, calling them orphans. In a furious climax, Saravanan poisons their food and burns them, sparing only his mother, with Meera surviving long enough to witness the carnage before Saravanan bludgeons her.
In the present, Vetri discovers the grim truth behind the murders, but Guru kills Vetri to keep the conspiracy quiet. The ghosts, who finally understand the reasons for their deaths, enact their revenge by killing Saravanan, Guru, and Guru’s henchmen. When Senthil and his friends leave the house, they discover a bag of cash in Saravanan’s car and, fueled by a newfound purpose, convert the house into a retirement home. They live out their days in the once-haunted space, now inhabited by Kamala, who had recovered from amnesia, and a growing community of elderly pensioners who had been abandoned by their children, finding a peaceful, if unconventional, happiness in their new home.
