The film opens with a prologue, in which a person is being taken to a hospital and the doctor later reporting that the person's condition will be known only after sometime. The scene then shifts a few months back. Enter Kathirvelan aka Kathir (Udhayanidhi Stalin), a Madurai-based minibus owner who is a devotee of Lord Anjaneya since the age of five. Due to his devotion for Lord Anjaneya, he does not show any interest in women. One day, while returning from an Anjaneya temple, he sees his elder sister Vineethra (Chaya Singh) crying outside his house after his father (Aadukalam Naren) refused to take her in, having disowned her for eloping with a Coimbatore-based mill owner Shanmugham (Dr. Bharath Reddy) against his wishes. Vineethra however, now has issues with Shanmugham, as a result of which she left him and returned to her father's house. On Kathir's cajoling, his father reluctantly accepts Vineethra into the house. Kathir then decides to find out what caused the standoff between Vineethra and Shanmugham and leaves for Coimbatore, lying to his father that he is headed for Salem to do some work related to his minibus business. Before leaving, he is warned by Vineethra not to fall for her (Nayanthara), as her father and Shanmugham are sworn enemies. The movie ends with Kathir and Pavithra getting married happily.