The film begins with two Indian agents working under Ranvir Singh ( Manoj Bajpai) chasing an international arms dealer Mikhail ( Prithviraj Sukumaran) , but instead he kills them both and escapes. A year later Shabana Khan ( Taapsee Pannu) a college student who is also Judo fighter is been followed by Indian agency as a potential recruit. And one of her friends Jai ( Taher Shabbir Mithaiwala) who likes Shabana always tries to hit on her. A day before Jais birthday he asks her for a date and she agrees to go with him to the date and confesses his love for Shabana and asks her about her past and she tells him that she had been kept in juvenile home for killing her abusive father who used to physically assault her mother. That fateful night, During their bike ride home, Shabana faces eve teasing from a group of four drunk men in a jeep. Later it turns into a physical altercation resulting in Jai getting killed and men running away. Soon after, Shabana receives a call from an unknown number asking if she wants to avenge her lovers death. The unknown caller agrees to help her persecute the killers in exchange for Shabana joining a secret agency. Shabana agrees to this and accordingly receives information on the killers whereabouts and aids her in killing them. Shabana then reaches Goa to the same hotel where the main culprit who killed Jai was staying. As instructed Shabana enters his room killing him and later escapes with the help of Ajay Singh ( Akshay Kumar) . The unknown caller is revealed to be Ranvir singh.
Following this Shabana is recruited into the secret agency on a trial basis, wherein she is to receive extensive training in physical fitness and fighting techniques. The story then focuses on a global arms dealer and supplier called Mikhail, who has been on the radar of several intelligence agencies. Three Indian Agents then tracks down Tony considered as Mikhails right hand. During interrogation Tony tips them a German Doctors name who has surgically changed Mikhails face. By the time agency contacts the Doctor to get Mikhails new look, Tony kills all three agents and escapes, revealing that he himself is Mikhail. Ranvir Singh gets the tip that Mikhail is planning another plastic surgery to change his face again. This time Shabana is sent to kill Mikhail, with the help of Ajay Singh and Om Prakash Shukla ( Anupam Kher) . Shabana enters the hospital disguised as a patient. After getting rid of Mikhails private security, Shabana is about to kill Mikhail in OT. To her surprise Toni is very much awake, as he had refused to take anesthesia during operation. After quite a tussle, Toni almost strangles Shabana. But finally Shabana manages to kill Mikhail and escapes from the police, once again with the help of Ajay.