During a handoff of suspected terrorists at the airport, he is called by his daughter's indignant school principal regarding pills found in his daughter's possession.
The handoff is botched, but the suspects are injured and apprehended. The TASC team, upon interrogation, find out that they are a part of a sinister plot for a large-scale attack somewhere in the country. However, its details remain elusive until Tiwari is sent to the turbulent region of Kashmir in North India. There, after briefly slipping into the Pakistani region of Balochistan, he is able to uncover the plot, codenamed Mission Zulfiqar, which involves smuggled nerve gas being used to mount an unprecedented attack on the country's capital of New Delhi.On the home front, Tiwari's relationships with his wife and kids suffer due to his constant absence. His wife Suchitra, fed up with handling the household and kids all by herself, begins to look for professional (and personal) opportunities in her husband's absence. Tiwari's crumbling family life is further emphasized when we see his young son Atharv find his father's gun and, left alone at home, proceed to dangerously role-play with it.
By the time the agent returns from his clandestine mission in Kashmir, there is a marked distance between him and his wife, which he tries to half-heartedly close but to no avail. His daughter also berates him for being detached from the family and hints that her mother might be having an affair, something Tiwari is seen being suspicious of earlier. Tiwari's son attempts to blackmail his incredulous father for a new mobile phone by threatening to uncover the fact that he has stashed a gun at home.Tiwari is pulled back into the quickly emerging terrorism crisis as he realizes that the explosive Mission Zulfiqar is aimed at attacking India as well as destabilizing the Pakistani administration. With the governments of the two countries cooperating by sharing information, Tiwari and his team ambush the nerve gas canisters whilst they are being transported to Delhi. However, Sajid, the man transporting them, escapes.
Sajid then reaches Delhi and joins up with his longtime ally and notorious terrorist Moosa, who is also known for his war crimes in Syria and is 6th on the FBI's most-wanted list. He informs Sajid that he secretly worked on a "Plan B" and that despite the canisters getting captured, their plot to attack New Delhi will go ahead as planned.
Tiwari, amidst celebrating with his team the foiling of the terrorist plot, is informed about the existence of a Plan B. Left with no other option, he circulates the photographs of Moosa and Sajid all over the country in the hope of finding any information that will help locate them. This leads to Moosa's mother being found in a small village in South India. Tiwari, aware of the terrorist's attachment to his mother, then proceeds to circulate a video of the mother pleading to her son to turn himself in.Moosa and Sajid, meanwhile, break into a chemical factory in Delhi and force the supervisor to override its safety protocols. Moosa, an engineering student in the past, begins to mix the factory's massive stores of chemicals to release a poisonous gas over the entire city. He details to Sajid how the gas, like the Bhopal Gas Tragedy, will disable and disfigure the residents of the city for generations to come.