Arasu movie is the story of Thirunavukkarasu(Sarathkumar) who is a mild mannered, quiet man, arrives at the agrahaaram in Kumbakonam to take up the job of handling accounts at the temple. He is helped by the family of Velu Shastri('Delhi' Ganesh) and Velu Shastri's daughter Meera(Simran) falls for him too.But news of a dangerous rowdy being released from a nearby jail brings out the real Arasu - a man who is out to take revenge on the men responsible for several atrocities, including the murder of his parents(Sarathkumar and Roja).