Kanthaswamy is a CBI officer in the Economic Offences Wing, and along with his friends, grants the wishes of the needy who write letters to the great Lord Muruga temple by disguising as an anthropomorphic rooster superhero known as Kanthaswamy. During a CBI raid, he discovers a stash of black money owned by Pallur Paramajothi Ponnusamy aka PP Ponnusamy, a rich and corrupted entrepreneur, and his partner Rajmohan. Ponnusamy pretends that he has a stroke to escape questioning by the police. Ponnusamy's daughter PP Subbulakshmi gets angered by the news that her father is sick. So she goes after Kanthaswamy to seek revenge by pretending to be in love with him. Kanthaswamy, knowing her real intentions, plays along. This forms as a cat-and-mouse chase between the two. Eventually both fall in love with each other. In a parallel comedic role, Thengakadai Thenappan is also sought after by a local police inspector who tries to solve the mystery of "Lord Muruga saving the people".
In a series of twists, the police inspector is able to bring out the truth that the CBI is involved in the role behind the secret work of helping the needy people, though he could not be able to confirm it. Kanthaswamy finds Subbulakshmi's family bank account password in which the black money is illegally saved. He tricks Subbalakshmi into revealing the password and answers for the security questions indirectly. Kanthaswamy transfers the money to his own account, which he would use for helping poor and needy people. In the end, Ponnusamy gets stroke upon knowing that his black money had been robbed and that the account has zero balance, where they had stored it. After that, Subbulakshmi and Kanthaswamy get married and live in Rajasthan. Kanthaswamy sees some letters tied to a tree, just like the ones at the Lord Muruga temple. He reads one letter and puts it into his pocket with a secret smile, implying that he will pursue being the rooster superhero again.