Plot

A pizza delivery boy lands in a mysterious circumstance and it works a dramatic change in his life.

Michael (Vijay Sethupathi) lives with girlfriend Anu (Ramya Nambeeshan) and works as a deliveryman at a pizzeria. One day, Anu announces that she is pregnant and he is faced with a dilemma. They decide to marry and save up for a big bash later. But during a routine delivery one day, the pizza crumbles...—Anonymous

Michael Karthikeyan is a pizza delivery boy who lives with his girlfriend, Anu, an aspiring novelist researching material for a horror story. Michael does not believe in the supernatural but is afraid of anything paranormal. Anu keeps telling him that he will soon realise the presence of supernatural beings. At first, Michael is confused and scared, and his fears are confirmed when he discovers that a spirit possesses his boss, the Pizzeria owner Shanmugam's daughter.

Meanwhile, Anu becomes pregnant, and after a brief altercation, Michael and Anu get covertly married. One particular day, Michael goes out to deliver a pizza to a customer and returns to the restaurant in shock while covered in blood; he keeps muttering Anu's name, seemingly worried about her. When his boss questions him, Michael explains that he had been to deliver a pizza to a customer named Smitha in a bungalow and recounts the events at the place.

Smitha requests Michael to wait downstairs while she goes upstairs to get money for the pizza. Almost immediately, the power goes out, alarming Michael. While waiting downstairs, Michael hears a loud unidentifiable noise from the bedroom upstairs. Going up to investigate, he finds Smitha murdered suspiciously and notices a slice of pizza he had delivered is missing, suggesting that there may be somebody else in the house. Horrified, Michael dashes to the door only to realize it is locked from the outside.

Furthermore, when the murdered woman's husband Bobby arrives, he at first believes he stumbles upon his wife having an affair. Through his cell phone, Michael communicates with Bobby and explains his situation thoroughly, instigating Bobby to aid him in getting out of the house. Moreover, Bobby suddenly disappears from the front entrance and is found by Michael inside the house, mysteriously murdered in the same room as his wife, with two slices of pizza now missing. Also, Michael encounters the couple's child "Nithya", identical to the spirit's name allegedly possessing Shanmugam's daughter.

Michael tries everything to get out of the house, including breaking down the sealed doors leading outside and using the house phone, which works even though the line is dead. He manages to contact Anu using the phone and gets her to contact the local police. When a couple of officers arrive at the bungalow, Michael believes that Anu had requested them to help him, but they reveal that four people died in that house- Smitha, Bobby, their young daughter, and a girl named Anu, implying that she is Michael's girlfriend, Anu. The police disclose that Michael is a suspect and attempt to arrest him. Confused, Michael does not believe them and attempts to escape to search for Anu.

Michael then witnesses the police getting dragged into the house and killed. At this juncture, Michael, in a horrified state, runs back to the restaurant. While Michael is unconvinced that Anu is dead, his friends at the restaurant and Shanmugam start realising they had never seen Anu; they also observe that Michael's home does not have any evidence that he lived with Anu. Also, the haunted bungalow witnessed the untimely deaths of a married couple, their daughter, and two police officers whose ghosts Michael interacted with earlier. Meanwhile, Michael seems to continue his search for Anu, has constant health issues, and seems to be disturbed by supernatural entities.

As Michael stops and calls Anu during a delivery, the true story of what had happened is disclosed. The Income Tax department had planned a raid on Shanmugam's house. Shanmugam, who has diamonds worth around 20 million hidden in his restaurant, hides them in a candy box and asks Michael to deliver them to his house. But Michael has a bike accident and comes in contact with the hidden diamonds. Michael and Anu decide that stealing those diamonds would improve their lives and support their baby. So, they concoct a clever story in which Michael convincingly "forgets" the Pizza bag at the "haunted" bungalow, which Shanmugam would never enter into, given his fear of the supernatural. Meanwhile, Anu has left for Kochi via Bangalore with the diamonds and her belongings and obtained fake documentation using which Michael and Anu can settle abroad.

After the phone call, Michael goes to deliver a pizza to a house and encounters a series of events similar to the story he had narrated. Inside, he meets a girl identical to the "Nithya" described in his tale. Michael is locked inside the home with "Nithya" curiously looking at him. The lights then go out.