The story of the film revolves around the concept of Ifrit and Auladhchakra, a satanic cult in Bangladesh aiming to propagate and progress the bloodline of Ifrit. They branded the women impregnated by Ifrit with the symbol of a foetus on their skin. Rukhsana (Anushka Sharma), is the daughter of a woman who was a victim of a ritual by Auladhchakra. She is afraid of incense sticks and religious hymns and prayers, and hides her head in a bucket of water to cut out the Azaan playing in a nearby mosque. Professor Quasim Ali (Rajat Kapoor) used to head a group of vigilantes which sought out women impregnated by Ifrit, and killed their babies by chopping off their heads. This drew a lot of flak from villagers eventually and the group was ultimately shut down due to its radical approach.

The film begins with Arnab (Parambrata Chatterjee) meeting Piyali (Ritabhari Chakraborty) on the roof of her house. Arnab has come to meet her for marriage arranged by his family. Piyali is a nurse, while Arnab runs a printing press. While returning from her house, in the heavy rain, with his father driving, they hit an old woman. Although the woman died by being run over, Arnab files the case with the local police inspector (Santilal Mukherjee) as attempt to suicide. On visiting the accident spot, they discover the place where the old woman used to live, locally called kuttewali budhiya, meaning dog lady, in a hut in the forest by the road. Rukhsana is found chained in a dark corner of the hut, pale and bruised. Arnab takes pity and after taking Rukhsana to visit her dead mother, he decides to take her in later in the film.

Meanwhile, a mortuary assistant (Dibyendu Bhattacharya) who made a living stealing golden teeth and the likes from corpses in the morgue, and who initially worked with the professor, discovers that the dead woman, Rukhsana's mother, has the mark of foetus on her skin. He decides to inform the professor and they decide to seek out Rukhsana. They reach Rukhsana's hut in the forest, only to find that she had escaped. Later they track down Rukhsana to Arnab's house, where she was supposed to stay until he found housing for her.

Rukhsana seemed to have been abused since her childhood. Arnab observes that she doesn't have a soul to care for her, and hence takes care of her. Rukhsana inadvertently falls in love with him, but also has hallucinations of herself bleeding when she is alone. The professor meets another old woman, supposedly born of Ifrit, a kalapori(Mansi Multani), who seemingly can communicate with others like her. She tells him where Rukhsana is, and that she is going to seduce the guy she is living with to pass on the bloodline.

One night, Rukhsana gets the urge to spew poison out of her system, as her body generated poison every month due to the Ifrit blood, and kills a dog near Arnab's house in the middle of the night. The professor ultimately approaches Arnab and tells him her story, but he refuses to believe him. One evening, the morgue assistant follows Arnab, and they end up in a scuffle, leaving Arnab bleeding. Rukhsana tends to him and tells him of her affection for him. She also kills the morgue assistant who had hit Arnab. She finally succeeds in getting impregnated by him, but then her attitude changes. She forces him to stop meeting Piyali, whom she sees as competition. On further argument, she grabs him by his throat and lifts him clear off the ground. This brings him to contact the professor and find out more about Ifrit.

The Ifrit cannot be seen but only heard by its breath. Ifrit babies can be born by latching on to human wombs. The babies are born over a month instead of nine months, and without an umbilical cord. So when Rukhsana tells Arnab that she is pregnant, he contacts the professor to take care of it. Piyali had come by his house once, and finding Rukhsana in his room accidentally, breaks all contact with him. So, while the professor tortures Rukhsana so that she died of her own venom, Arnab withdraws himself from his normal life and society, and stays at his parents' home.

After one month, Piyali comes over to tell Arnab that he must convince his parents that she isn't the reason for his voluntary loneliness, but instead gets to hear the truth about Rukhsana. She also confesses about an earlier relationship and an aborted baby of her former boyfriend. But things soon take a turn for the worse.

On the last day of the month, Rukhsana sets herself free. She kills the professor and his men before heading over to Piyali's house. Arnab heads over to his own house to find the others dead, and hurries over to Piyali's house. Rukhsana manages to injure Piyali, but is momentarily distracted by an accidental push on the TV remote, which turns on a cartoon show she used to watch at Arnab's house. Piyali frees herself and hides. But then, Rukhsana goes into labour, and Piyali, being a nurse couldn't bring herself to kill her. She eventually helps Rukhsana have her baby, which is shown having an umbilical cord. Rukhsana leaves the baby to Piyali, while Arnab rushes to the old hut where Rukhsana goes back, injured and near-death. In her last struggle to spew poison into Arnab or let it remain her system, she chooses the latter and dies. Before dying she tells Arnab that the baby isn't like her and is human. The film ends with Arnab saying that Rukhsana's love made the baby human, rather than Ifrit's hatred.

• Anushka Sharma as Rukhsana
• Parambrata Chatterjee as Arnab
• Rajat Kapoor as Professor Quasim Aali
• Ritabhari Chakraborty as Piyali
• Mansi Multani as Kalapori
• Mithu Chakraborty as Arnab's mother
• Rohit KaduDeshmukh as Arnab's friend
• Santilal Mukherjee as Police Inspector
• Dibyendu Bhattacharya as Morgue worker
• Arijit Dutta
• Sraboni biswas

The first look of Pari was released on 13 June 2017 by Sharma via her Twitter handle. The film's motion poster, promotionally called Screamer, was released on 9 January 2018, showing the face of Sharma's character getting bruised. A 30-second clip, the second "screamer", was released on 3 February 2018, which showed Sharma watching a cartoon on television with an idyllic smile, giving the impression that she is safe and okay. However, the camera pans to show that her hands and feet are bruised, and she is chained to the bed. The official teaser of Pari was released on 7 February 2018 by Sharma via her Twitter handle. The third screamer, released on Valentine's Day, opens with Anushka and Parambrata's characters watching television when Anushka says "I love you" to him. She becomes disturbed when she hears an eerie female voice respond, "I love you too." The camera pans to show a bloody and battered version of herself, grinning and terrifying the real Anushka. The official trailer of Pari was released one day later, on 15 February 2018. After the trailer, two other screamers have been released.^[13]

During the shooting of the film in August 2017 at Basanti State Highway, 24 Pgs. (S) district of West Bengal, a technician was electrocuted. The shooting of the film was immediately stopped but was started again after a while.^[14]

The film has been banned in Pakistan for allegedly promoting Black Magic, some non-Islamic values and anti-Muslim sentiments.^[15]

The music of Pari was composed by Anupam Roy while the lyrics were written by Anvita Dutt.^[17]

Critical response

Pari received negative reviews. It has an approval rating of 50% on review aggregator website Rotten Tomatoes based on 6 reviews with an average rating of 5 out of 10.^[18] Rajeev Masand of News18 gave the film a rating of 2 out of 5 saying that, "Pari doesn't come together in a coherent, satisfying way. What starts out interestingly, ends in a mess."^[19] Rohit Vats of Hindustan Times gave the film a rating of 1 out of 5 and said that, "Anushka Sharma's film Pari is a confusing tell of ghosts, ghouls, djinns and forced legitimacy. Pari appears puzzled as if they don't know how to end what they started. With 136-minute screen time, Pari doesn't head anywhere."^[20] Lakshana N Palat of India Today gave the film a rating of 2 out of 5 saying that, "The story of Pari is submerged under irrelevant scenes, jump scares, and the desperate need to fall into the horror-film category. It's a shame, because the storyline was actually quite a unique and interesting one."^[21] Shubhra Gupta of The Indian Express gave the film a rating of 1 out of 5 and concluded her review by saying that, "Anushka Sharma plays Rukhsana with a great deal of bloody enthusiasm. You cannot accuse her of not trying hard, but the film is so poorly-written, and so scatter-brained that nothing can rescue it."^[22] Saibal Chatterjee of NDTV said about the film that, "It lacks the narrative consistency that its in-your-face methods needed in order to be truly effective. In the end, the makers of Pari try way too hard. The outcome is an extended blur that leaves you dazed but totally unimpressed." and gave the film a rating of 2 out of 5.^[23]

• List of Hindi horror films