A mathematician genius, Mathi, has another identity, Cobra, who commits intelligent crimes using math.

A serial killer (Anurag Kashyap) disrupts peace in Bengaluru by kidnapping. He goes by the name of the highly notorious serial killer Rudra, who was announced dead five years ago. After another such case, in which the CBI are involved headed by Anjali (Nayanthara), he goes live and declares himself as the deceased Rudra. He insists that Rudra is still alive and announces that he is now back in action. Anjali, who dealt with the earlier case of Rudra, is appointed to deal with him.
In a parallel storyline, Anjali’s brother Arjun (Atharvaa) is facing a rough phase in his relationship. The film flashes back to his life with his lover Krithika Rao (Raashi Khanna) and how they eventually break up. To make it up to her, he, with his friend Vinoth (Ramesh Thilak), travels to Bangalore to meet her and enters the deadly scene between Rudra and Anjali. The cat-and-mouse game gets too intense when Rudra brings Arjun into the game by kidnapping Krithika and demanding a ransom from her father. In an effort to save Krithika, Arjun follows Rudra’s orders and gets framed as “Rudra”, making things much more complicated for him. Anjali is suspended, and Officer Narayan (Devan) takes over the case.

Raghavan (Sananth), an aspiring filmmaker, narrates a horror story to a film producer (Singampuli), who instead asks for a comedy. Sajith (Abhishek) is an electrician living a miserable life, while Vimal (Ramesh Thilak) is a graphic designer. Their friend Srinivasan (Arulnithi) is involved in a platonic relationship with Jillu (Jangiri Madhumita), a married woman, in return for money. Out of false bravado, the four men decide to visit a dilapidated mansion in De Monte Colony, which is rumoured to be haunted. They sneak into the house and get separated in the darkness and have a chilling and forgetful experience, although all of them manage to come out seemingly unscathed.