The film starts with Ashok Kumar aka AK (Ajith Kumar) setting bombs in three places and informing the police about them. Before the police arrive, the bombs are set off. He along with his lady love Maya (Nayanthara)both threaten her old college mate hacker Arjun (Arya), who starts hacking one system after the other. AK then threatens Sriram Raghavan (Aadukalam Naren) by trying to kill his child so that he can extract the truth about black money. AK murders him in a fit of rage. Arjun, who is particularly irritated by the things happening around him, complains about the misdeeds of AK to Inspector Prakash (Kishore). When AK gets closer to achieving his goals, Arjun gives him away to the police and the both are arrested. Arjun is later released after his true identity is revealed.
Later, Maya, who had escaped from the scene, tracks Arjun and Anita * (Taapsee Pannu) and tells them AK’s original motive. AK is revealed to be a former member of an Anti-Terrorist Squad, who is on a mission to expose a scam regarding faulty bulletproof jackets, that are provided to security forces, which resulted in many bloody deaths including his best friend and colleague, Assistant Commissioner Sanjay (Rana Daggubati). It turns out that Home Minister Mahadev Rane (Mahesh Manjrekar) and his associates Milind Virekar (Atul Kulkarni) and Ramya Radhakrishnan (Suman Ranganathan) are the people involved in the scam. Ramya kills Sanjay’s pregnant wife and her parents by poisoning while Maya, who is also poisoned, and Mango (Five Star Krishna), who was placed on a railway track, survive the attack. Arjun, who hears the flashback, decides to help them.
AK and Arjun arrive at Dubai to meet Deeksha (Akshara Gowda), the daughter of Mahadev Rane. Arjun enters a bank in the guise of a service engineer, opening an account so that AK can transfer all the money of the minister into his account. Maya kills Ramya by pushing her off a building. Deeksha later finds out their plan but later she is threatened at gunpoint by AK. AK, Arjun and Maya later arrive in Mumbai but they come to know that Mahadev has kidnapped Anitha (Taapsee Pannu), who is Arjun’s girlfriend. AK tactfully kidnaps Deeksha and Durrani (Murali Sharma) in Kashmir. Mahadev arrives at Kashmir with Anitha. Here, both Durrani and Deeksha get killed in the mayhem while Anitha is saved. AK kidnaps Mahadev and ties him to various bombs and he questions his corrupt activities. Prakash, who arrives there, calls AK to defuse the bombs. AK advises Prakash to think from the point of view of a common man, instead of a policeman, to think whether it is right on his part to save a corrupt person. Prakash later changes his mind and asks the other policemen to leave him. Mahadev is killed in the blast. Arjun and Anitha get married while AK transfers all the illegal money of the minister to Reserve Bank without revealing his appearance. Arjun and Anitha later get kidnapped in Jordan during their Honeymoon trip, only to know that AK has brought them for another mission.