
Lakshman is perplexed and fails to recollect the incident. Later that evening, Sanjay mistakenly attacks and kills one of Lakshman's goons in the parking lot. He meets Chitra at the function who, after some conversation, decides to befriend him. Sanjay took pictures of Lakshman and decides to kill him. He tracks down Lakshman to a college function where Lakshman is the guest of honour. When the inspector is about to read the 2003 diary, Sanjay returns to senses, attacks him and ties him up. The diary ends with Sanjay proposing to Kalpana and promising himself that he will reveal himself as Sanjay Ramaswamy if she accepts. Eventually both of them hang around together and gradually develop a liking towards each other. As soon as Sanjay knows of this matter, he decides to confront Kalpana but falls in love with her on first sight. Kalpana thinks of this as an innocent prank that may fetch her better modelling work, and decides to play out the charade as Sanjay's girlfriend. The owner of Kalpana's advertising firm (Manobala) misinterprets this as a romantic advance, and in view of a possible lucrative Air Voice ad campaign and other benefits, encourages Kalpana to accept the overture.

In the course of his business, Sanjay sends his men to meet Kalpana, a struggling model, about putting up a billboard above her apartment. Sanjay Ramaswamy is shown as the owner of the Air Voice mobile telephone company. The film flashes back to 2002 as the inspector reads the diary. The inspector finds two diaries where Sanjay has chronicled the events of 20. His main target is a man named Lakshman (Pradeep Rawat), a notable social personality in Chennai.Ī police inspector (Riyaz Khan), on the case of the serial murders, tracks Sanjay down to his flat and attacks and disables him. It is revealed that Sanjay is ultimately out to avenge the death of his sweetheart Kalpana (Asin), and that he is systematically killing the people who were responsible for it. Sanjay uses a system of photographs, notes, and tattoos on his body to recover his memory after each cycle. It is revealed that Sanjay has anterograde amnesia where he loses his memory every 15 minutes. He takes a Polaroid picture of the man, and writes on it "done".

Sanjay is introduced as he brutally murders a man. Chitra, nonetheless, decides to investigate the matter herself. Her professor denies access to Sanjay's records as it is currently under criminal investigation. She wants to investigate the curious case of Sanjay Ramaswamy (Suriya), a (former) notable Chennai based businessman, who is reported to have anterograde amnesia. The film opens with Chitra (Nayantara), a medical student in a college in Chennai, and her friends working on a project about the human brain.
