The movie begins with Sivan (Mohanlal) who is a Madurai-based don, being cornered by a gang while taking his pregnant wife (Poornima Jayaram) to the hospital. He manages to thwart the gang, following which he adopts his slain driver’s son Shakthi. Shakthi witnessed his father being killed by a police officer during the fight, which induces a hatred for the police in him to such an extent that he does not tolerate others wearing a khaki shirt or even dreaming of becoming a police officer, including his friend Gopal (Soori), who aspires to join the police when he grows up.
Several years later, Shakthi, now a young man (Vijay), has become Sivan’s most trusted aide, assisting him in his criminal activities and also twinning as his bodyguard and driver. His aversion for the police has not waned, even rejecting a woman named Shanthi (Kajal Aggarwal), for whom he had an infatuation after witnessing her admonishing two female police constables (Jangiri Madhumitha and Vidyullekha Raman) taking a bribe until he found out that she is a police inspector herself. Life goes smoothly for Sivan and Shakthi until the new police commissioner for Madurai (Pradeep Rawat) takes charge. The commissioner takes Sivan to the outskirts of Madurai, threatens him to quit his nefarious activities or else face arrest, following which he leaves him there. This incident leaves Sivan humiliated, prompting him to force Shakthi to join the police to save his crime syndicate and prove the commissioner’s word’s wrong (A policeman can think like a criminal, but a criminal can never think like a policeman). Shakthi, due to his hatred for the police, deliberately fails the exam and physical tests required to become a police officer, but still ends up becoming a police officer due to Sivan’s “backroom dealing”. Shakthi reluctantly takes up the job as Assistant Commissioner, giving Sivan and his henchmen a free rein to perform their criminal activities. However, after witnessing a mass scale destruction caused by Sivan and his gang, which led to the death of several innocent people, including children and mothers, being admonished by Shanthi for showing disrespect for the police profession, and witnessing the assault of a woman (Meenal) (who had come to the police station to lodge a complaint against Sivan for being responsible for the death of her husband due to the destruction) at the hands of Sivan’s gang, he changes gears and decides to become an honest and upright police officer. He lodges Sivan’s henchmen in prison, and tries to convince Sivan to give up his criminal activities, which does not go well with him, forcing them to part ways.