Vikram, a high-profile fashion and wildlife photographer, watches a video in which Roshni tells him she is leaving him, a painful moment that leaves him distraught. He drowns his heartbreak in a bar and soon meets Nisha Sengupta, and the pair quickly fall in love. Nisha moves into the flat Vikram shared with Roshni, changing the dynamics of the home and setting the stage for the unraveling events to come.
Vikram becomes a suspect in the disappearance of Roshni, but the investigators find no evidence connecting him to what happened.
It is revealed that the house is owned by a British lady who shows Roshni a secret room built to hide her husband just in case someone came to look for him because he was in the Indian Army in 1947. The room is self-contained.
In a flashback, it is also shown that Roshni, jealous of Vikram's relationship with one of his colleagues, decided to pretend she was leaving him. She creates the video saying she is leaving as she hides in the secret room. The room has some one-way mirrors where she can observe Vikram's reaction. When she decides he has had enough she looks for the key and realises she lost it and is now trapped in the room with no way to contact him.
Nisha finds the key to the secret room, but she does not know what it is used for. Nisha eventually figures out that Roshni is trapped in the house because Roshni is able to communicate through tapping on the pipes in the secret room. As Nisha is ready to open the door, she pauses and decides not to rescue Roshni because she might lose Vikram after that. Nisha struggles with her decision, but decides to open the door and check on Roshni when the investigators give Nisha a package containing some images. As Nisha is checking on Roshni laying in a bed in the secret room, Roshni surprises Nisha and knocks her out with a glass bottle and leaves Nisha locked in the room. After Roshni comes out of the secret room, she sees the images and the package, which are pictures of Vikram and his colleague in compromising situations, shattering her. She decides to leave the house. She leaves that picture of Vikram with his colleague on the mirror and also sticks her necklace to show Vikram that she is out and then she sends the keys to the room to the investigator who actually loves Nisha. The investigator comes and arrests Vikram while Nisha is stranded in the room as both Vikram and the investigator have no knowledge about the room or the key. The final scene shows Roshni tearing her and Vikram's photograph and going on a highway road in a car alone, happy to leave the devastated and arrested Vikram.
