In 1920 British India, Arjun Singh Rathod is a renowned architect who has gone against his wealthy Hindu family's wishes to marry a British Indian woman – Lisa Singh Rathod. His family ambushes his car en route to Bombay, assaulting him badly and setting the car on fire in an attempt to kill Lisa. Due to this, Arjun, once a deeply religious and devout Hindu, shuns his beliefs and abandons his family for his wife.
Meanwhile, in Palampur, a rich businessman has acquired a stately old manor and plans to turn it into a boutique hotel. However, his estate manager M.K. has difficulty in retaining an architect for the place as the two prior architects died under mysterious circumstances. Arjun wins the contract, so he and Lisa move into the manor as he begins his survey of the property. Lisa begins experiencing strange noises and feels afraid. She inquires with Balwanth, the caretaker, to confirm her suspicions, and he rebuffs her and hints that she may have imagined it. Arjun attributes her experiences to anxiety from their recent escape and the fact that the countryside is quieter than the city. When he visits M.K., he points out there is a sealed room at the back of the manor he will need access to as he needs to survey every part of the house. The manager readily agrees and tells him he has full authority to do as he wishes within the house as the owner was wanting to start the renovations as soon as possible. Lisa, in the meantime, explores the house and finds the sealed room but the door is now open – inside she discovers a library with a magnificent piano and a portrait of a beautiful woman in Indian royal attire. She plays the piano and is soon disturbed by the feeling of someone watching her. Later that evening she and Arjun argue when she finds the room is sealed again and he refuses to believe her description of the room.
Balwanth feels it is dangerous to allow people into the manor due to the prior deaths. He accuses M.K. of being aware of the manor's dark secrets as he refuses to visit the house due to his own fears, but M.K. threatens to fire him and buys his silence on the matter.
Lisa, in an attempt to gain solace, visits the village church where she befriends Father Thomas. Confiding her worries and fears in him, Father Thomas reassures her that he will come by the house to bless it. Meanwhile, Arjun has workers remove the doors of the library and is surprised that Lisa's description of the room was correct. Later that night, Lisa is tormented by an unknown spirit in the library where she sees the portrait has a name on the bottom – Gayatri.
The next day, Arjun leaves to survey the vast property for a few hours and Lisa has Father Thomas bless the house, during which he discovers the manor is cursed and has held on to its dark past. Later that night, Father Thomas is tormented by a spirit whispering in Latin. He rushes to the church archives where his colleague discovers the phrase means the house and its spirit are warning the church away.
Father Thomas rushes to the manor to warn the occupants but discovers Arjun has taken Lisa to Delhi for a few weeks for a high-profile meeting with the project suppliers. Father Thomas begs Balwanth to pass on a message to Lisa and Arjun that it is dangerous for them to stay in the house, and he promises to do so. On the road to Delhi, Arjun's carriage is stopped by soldiers who inform them the roads are dangerous due to Indian rebel fighting with the British further down the road. As Arjun cannot afford to waste time, he leaves Lisa at home and proceeds with his trip with armed guards. Balwanth does not pass on Father Thomas’ message when Lisa comes home, and she falls badly sick after a night of terrors. The church windows begin to bleed and Father Thomas fears Lisa is at great risk.
When Arjun comes home to his gravely ill wife, he enlists a doctor's help who urges him to get her admitted to the hospital. Father Thomas tries to tell Arjun that Lisa is possessed but he is doubted – at the hospital Lisa's condition worsens as the spirit finally manifests itself. When the doctor and his staff attempt to sedate her, the spirit informs everyone of how the doctor raped his superior's young daughter by sedating her in that very room. Shaken by his secret being let out, the doctor agrees to let Arjun try religious methods to save Lisa. Arjun visits M.K. and forces him to tell him the truth – but as the owner had only purchased the property two years prior, M.K. can only give him the name of the prior caretaker – Radha, who left to live in Naya Nagar when the property ownership changed.
Arjun leaves Lisa in the care of church members and goes to Naya Nagar where he tracks down Radha, now an old woman. Radha reveals that the house was once owned by Rai Bahadur, a wealthy Indian of royal descent. In 1857 revolt when Radha was a child, he was away fighting the British, leaving his daughter Gayatri and her maid servants Kesar Ma and Radha to run the estate with two old male servants.
One night, the manor occupants are disturbed by screams and find a man in an Indian Army uniform, staggering around the property, badly wounded. He states his name is Mohan Kant and that he barely escaped the slaughter of his unit – one of the groups Gayatri's father was leading, where over 90 men died at the hands of the British. The family sympathise and dedicate their time to caring for him, believing he is a patriot. During this time, Mohan becomes infatuated with Gayatri's beauty and she grows close to him.
A few days later, Kesar Ma catches him secretly liaising with a British soldier during the night and confronts him. He kills and dumps her body in the well and lies to Gayatri that she has gone home to her village where a relative was badly ill. Gayatri becomes suspicious but is interrupted by Radha's terrified state. Following her to the well, they discover Kesar Ma's body. Gayatri then searches Mohan's belongings, discovering to her horror that he was a British spy who was responsible for the death of the unit as he leaked information to his commanding officer, betraying the Indian patriots while he was waiting to go undercover for his protection.
Gayatri sends Radha with the message to her father's outpost in order to get help, and chooses to stay behind to seduce Mohan to delay his departure. She consummates their acquaintance in the library long enough for her father to arrive with his troops and hang Mohan in the same room. He vows to haunt the manor awaiting her soul so he can take it with him to hell.
Rai Bahadur refuses to acknowledge his daughter's sacrifice, sealing the room and disowning her for bringing shame to the family by sleeping with a traitor – banishing her to her grandmother's where she dies unwed and alone on 18 November 1896. Arjun surmises that this was the same night that Lisa was born, deducing that Gayatri and his wife share the same soul hence Mohan's current obsession in possessing her, the spirit was attempting to kill Lisa in order to fulfil his vow. He ruminates on Lisa's experiences in the house with regret, stating that his wife tried telling him many times that something was wrong with the house, but he had rebuffed her fears as baseless and silly.
Father Thomas tells Arjun he now has less than 24 hours to oust the spirit as the next day was the new moon at which time the spirit would have full control of Lisa's soul thus killing her. He suggests an exorcism. The church refuses to authorise the procedure without the bishop's permission but this would be no earlier than two weeks by which time it would be too late. Father Thomas defies his superior's orders and proceeds with the ritual. During the exorcism, Balwanth and Father Thomas die due to the strength of the spirit, Arjun takes up the process but is forced to re-evaluate his atheist stance in renouncing his faith. Finally he succeeds by using the Hanuman Chalisa. The spirit of Mohan is destroyed and Lisa is free.
Afterward, Arjun completes the project and he acknowledges his faith stating that Gayatri's soul was reborn looking for the love she was denied and now she and the manor are at peace.
