The corpse of Samyuktha, a 15-year-old student who was brutally murdered, is discovered. Arun Kumar is an aspiring filmmaker who wants to make a movie on psychopaths. After multiple rejections and pressure from his family, he becomes an Assistant Sub-Inspector of Police, with the help of his brother-in-law, Doss, a police officer himself. He moves in with his sister Kokila, Doss and their daughter Ammu. Ammu gets into trouble in school and asks Arun for help, so he meets her teacher Viji at school. He befriends Viji and her hearing and speech impaired niece, Kayal.
Meanwhile, Arun investigates the abduction of a school girl, Amudha. Arun finds similarities between Samyuktha and Amudha’s case, due to the mutilations on a doll found at Amudha’s house. But his attempts to convince his superior officer, ACP Lakshmi, go futile. A few days later, Amudha’s mutilated corpse is found. The pathologist Dr. Nandan, suggests that the perpetrator followed a similar modus operandi like Samyuktha.
Over the next few days, another hearing impaired girl named Meera, from Viji’s school is abducted and killed. The search leads to Inbaraj, a teacher at the new school Ammu is enrolled in. Inbaraj is a pedophile who forces girls into irrumatio. Ammu herself narrowly escapes Inbaraj when Arun nabs him after getting a tip off from another victim Sharmi. Inbaraj admits to being a sexual predator but denies the murder charges. In a bid to escape, he holds Venkat, a policeman, at gunpoint, but Arun guns Inbaraj down.