The story takes place in two different timelines: the present and 12 years ago. The two storylines are told in parallel through flashbacks.
In 2009, computer engineer and hacker Deven Shaw moved into a new house with his wife Poorva, 10-year-old son Anuj and 12-year-old daughter Mrinali. Deven buys an antique mirror to decorate his office. Unbeknownst to them, the mirror supernaturally induces hallucinations. Poorva has visions of her own body decaying, while Alan is seduced by a mysterious and ghostly woman named Rupali Dixit, who has mirrors in place of her eyes.
In 2020, Anuj is discharged from a psychiatric hospital after believing that no supernatural event was involved in the death of his parents. Mrunali spent most of her youth researching the history of mirrors.
Using her position as an auction house employee, she gains access to the mirror and takes it to the family home, where she places it in a room full of surveillance cameras and "kill switches" - up to the ceiling. A loaded anchor. Mrunali intends to destroy the mirror, but first seeks to document her powers, proving Anuj's innocence.
Over time in 2009, the parents became psychic; Deven isolates himself in his office, and Poorva surrenders herself to the pain and goes insane. All the plants in the house die, and their family dog Pluto disappears after being locked in the office with the mirror.
After seeing Mrunali Deven with Rupali, she tells her mother, and the parents fight. One night, Poorva goes insane and tries to kill her children, but Deven locks her up. When the family's meal is over, the children learn that their father is under the influence of the mirror, so Mrunali goes to seek help from her mother, and finds her tied to a wall, acting like an animal. Mrunali and Anuj try to go to their neighbors for help, but the neighbors do not believe their stories. When Mrunali tries to access the phone, she learns that all her phone calls have been answered by the same man.
One night, Deven frees Poorva from the chains and both the parents attack the children. Poorva briefly comes to her senses, only to be shot and killed by Allen. The children try to destroy the mirror but it deceives them, leading them to believe that they are hitting the mirror when they are actually hitting the wall. Deven also experiences a moment of clarity and kills himself by forcing Anuj to pull the trigger of the gun and shoot him, leaving a small crack in the corner of the mirror in the process. Before he dies, he asks the children to run, but Rupali and the other victims of the mirror appear as gruesome ghosts. Police comes and takes Anuj into custody. Before the siblings separate, they promise to reunite as adults and destroy the mirror. As Anuj is taken away and put behind bars, he sees the ghosts of his parents watching him from home.
Anuj tries to convince Mrunali that she is wrong and the siblings argue. When they notice that the houseplants are starting to wither, they review camera footage and find themselves doing things they can't remember. Anuj finally accepts Darpan's supernatural power and attempts to escape the house with Mrunali, only to be pulled back by the mirror's influence. Seeing her mother's hallucinations, Mrunali stabs her in the neck, only to realize that she has stabbed her fiancé Manish Puri, who has come to investigate her. They try to call the police, but only get access to the voices that used to talk to them on the phone as children.
At this point, they see their doppelgangers standing in front of the mirror inside the house. Realizing that 100 phone calls are not going through, they go back inside the house. Mrunali and Anuj start hallucinating on seeing the younger versions of each other. They split up, and each of them reliving nightmares from their youth. Anuj wakes up alone in the room with the mirror while a younger Poorva confuses her mother by pointing at the mirror.
Anuj activates the kill switch, realizing too late and unable to see that Mrunali is standing in his way, and he kills her. The police come and arrest Anuj, who is hysterical, just like they did when he was young. As both a boy and an adult, Anuj claims that the mirror is responsible. As she is taken away and put behind bars, Kayli's ghost in Anuj's adult avatar stands in the house with her parents.
