Akshay Kumar as SI Arjan Sethi
Rakul Preet Singh as Divya, a teacher and Arjan's love interest
Joshua LeClair as Christopher Fernandez / Agnes Fernandez
Sujith Shankar as Purushottam Tomar
Chandrachur Singh as Narinder Singh, Arjan's brother-in-law
Sargun Mehta as SHO Gudia Parmar
Gurpreet Ghuggi as Guleria
Hrishitaa Bhatt as Seema Singh, Arjan's sister and Narinder's wife
Renaye Tejani as Payal Singh, Arjan's niece, Narinder and Seema's daughter
The corpse of 15-year-old student Samiksha, who was brutally murdered, is discovered. Arjan Sethi is an aspiring filmmaker who wants to make a movie about psychopaths. After multiple rejections from film producers and pressure from his family, he becomes a SI in the Himachal Pradesh Police, with the help of his brother-in-law Narinder Singh, a police officer himself. While Arjan does have a significant rank, he is treated like a rookie, due to his lack of police experience. He moves in with his sister Seema, Narinder, and their daughter Payal. Payal gets into trouble in school and asks Arjan for help, so he meets her teacher Divya at school and they fall in love. He also befriends Divya's hearing and speech-impaired niece, Iti.
Meanwhile, Arjan investigates the abduction of a school girl, Amrita. Arjan finds similarities between Samiksha and Amrita's case, due to the mutilations on a doll found at Amrita's house. But his attempts to convince his superior officer, ACP Gudiya Parmar, go futile. A few days later, Amrita's mutilated corpse is found. The coroner suggests that the perpetrator's modus operandi is the same as Samiksha's. Over the next few days, another hearing impaired girl named Komal from Divya's school is abducted and killed. The search leads to Purushottam Tomar, a teacher at the new school Payal is enrolled. Purushottam Tomar is a pedophile who forces girls into fellatio. Payal herself narrowly escapes Purushottam Tomar when Arjan nabs him after getting a tip-off from another victim. Purushottam Tomar admits to being a sexual predator but denies the murder charges. In a bid to escape, he holds Parmar at gunpoint, but Arjan guns down Purushottam Tomar.
On the same day, Payal is abducted from her birthday party at home and Arjan finds her corpse in their car trunk two days later. To make things worse, Arjan is suspended for his negligence in shooting his gun when arresting Purushottam Tomar. Dejected and angry, Arjan unofficially investigates the case himself with the help of a few policemen. Finding an audio clip from Komal's hearing aid, he traces a piano tune back to a lady magician/pianist Agnes, who performed at all the victims' schools. Arjan informs his findings to SHO Parmar who believes him and re-appoints him on the case. Arjan finds that Agnes picks her victims by randomly calling them onto the stage, then kills them within the next few days and her next target would be a girl named Aisha. He tries to warn Aisha but despite constant surveillance, she is abducted. Arjan and his team track her location and save Aisha from being murdered. Agnes escapes and goes to Divya's house, where she attacks Divya & kidnaps Iti.
Arjan tracks Agnes to a nearby abandoned building and discovers that Agnes is a man. The man reveals himself to be Christopher, the son of Agnes, who was arrested years ago after killing a young girl similar to the other victims. Christopher reveals that he has progeria, and was bullied when he was younger. A young girl, Sofia, became friends with him when he was younger, but when he confessed his love to her, she humiliated him. Agnes invited Sofia to her home sometime later, where Agnes helped Christopher kill her. Agnes took the blame for the murder, but after her passing, Christopher decided to dress up as her and continue killing other girls, as they remind him of Sofia.
Arjan and Christopher fight, but thanks to Iti, Arjan is able to take him down. Divya comes to aid Arjan, as he & Iti walk away from Christopher's body.