Manohar moves into a new apartment, 13B, on the 13th floor with his family, fulfilling his life's biggest dream. But they encounter a series of small but strange incidents (such as milk getting spoiled), which are regarded as inauspicious by his family but shrugged off by an excited Manohar. The elevator in the apartment works for everyone in the building except Manohar, which bothers him.

The women in the family get hooked on a new TV show Yavarum Nalam (Everyone Is Well, or Sab Khairiyat in Hindi). The show is about a family eerily similar to Manohar's who have also just moved into a new house as they have. As the serial unfolds, Manohar notices that the incidents that happen in the serial reflect what is happening to his family. He notices that his camera takes distorted pictures of him while he is in the apartment but not while he is outside the apartment. Things like his sister graduating, his wife getting pregnant, and later suffering a miscarriage are all also shown in the serial. Priya is saved by their longtime family friend and doctor, Dr. Shinde/Dr. Balu. The rest of the family remains oblivious to the similarities, and Manohar prefers it that way to avoid panic.

Things take a turn for the worse in the serial, and Manohar becomes terrified that the same might happen to his family. He now wants to know who is behind the making of the TV show. He goes to the production company of the serial and asks about the serial Yavarum Nalam/ Sab Khairiyat. To Manohar's horror, he finds out that Yavarum Nalam/ Sab Khairiyat is a different TV reality show and realizes that the serial appears only in his house, every day at 1 p.m. One day Manohar finds their blind neighbour's dog trying to find something in the sand. Manohar stops the dog and takes it to its owner. Later that night, he asks his wife about the latest episode of the serial. She reveals the story to him of the neighbour's dog digging something, and the serial finishes for the day.

Manohar then wakes up at midnight and digs the ground on a rainy night, finding a diary with photographs pasted of the same family coming in the serial. However, there was also a picture of another guy he hadn't seen in the serial in the photos. He then unravels a terrifying secret: the apartment they live in shared their address with a house where a family of eight (similar to Manohar's family) was butchered back in 1977. It was the family of a TV news anchor named Chitra. On the day of Chitra's engagement, an ardent fan, Sairam Shinde, of Chitra, wanted to stop the engagement because he loved her dearly and said to them that if he did not get Chitra, then he would kill everyone without leaving a piece of them. But, he fails in convincing them. So, in sadness, he committed suicide the very next day. It was revealed that all members of Chitra's family were murdered with a hammer on the same day as Sriram's death. The blame rested on the lunatic brother in the family, as he had been seen with the hammer last. The police officer investigating the case also committed suicide by hanging himself in the same house.

Manohar and his policeman friend Shiva meet the mentally disturbed brother Senthil/Ashok (Hindi version), who apparently goes crazy after seeing a TV show in an asylum. They then meet Chitra's former fiancé Ramchandar, who tried to plead for Senthil's/ Ashok's innocence because he got covered in blood while he hugged the bodies of his family. After researching one night, Manohar has a nightmare of the 13B murderer climbing the stairs to kill his family. When Manohar tries to climb the stairs, he always ends up on the 2nd floor. Suddenly, Manohar wakes up from sleep, and he realises that the events that took place, from digging the diary of photographs to the climbing the stairs, are actually happening in his dream. He goes to the hall and witnesses the climax of Yavarum Nalam when they are showing the murderer's identity: Manohar's face is shown as the killer.

Not wanting to risk his family's life, he tells Dr. Balu/Dr. Shinde to book tickets and send his family members somewhere without telling him so that they would be safe.

Balu/Shinde arrives at Manohar's home and gives the flight tickets to Manohar's wife. Suddenly, the television starts when he comes home, and he sees Chitra's Spirit.

The 13B murderer is revealed to be Dr. Balu/Dr. Shinde. He killed them in the 1970s on behalf of his brother, the spurned fan, and also killed the police officer who caught him red-handed. Manohar kills Dr. Balu.

The story ends with Manohar living a normal life with a new dog in the family; the milk is not getting spoiled anymore. They bring Senthil/Ashok home, and the apartment's lift finally works for Manohar. When Manohar uses the lift the next day, he receives a call from Dr. Balu/Dr. Shinde, saying that while the 13B family had haunted the TV, he now haunts Manohar's phone. As the call ends, the elevator drops.