The story begins with Kattaalai (Moorthy) serving his sentence in jail. Kattaalai was a mentally ill man and he dreamed about getting married, the villagers took advantage of his innocence. Muthu Manikkam (Prakash Raj) was a respected village chief married to Devaatha (Raadhika Sarathkumar) but they didn't have children. Megala (Devayani), also known as Otta Rosa, was an innocent village girl who was rejected in her village, so she came to Muthu Manikkam's village. In the past, her mother was a stage dancer. When her mother fell ill, she became too a stage dancer and she was raped by her rich landlord. Her mother later died. Muthu Manikkam accommodated her in one of his house and fed her. Soon, Muthu Manikkam had an eye on her. He went to her house the night whenever he wanted. The rumour abounded that Muthu Manikkam and Otta Rosa had an affair. Later, Kattaalai's wedding was cancelled when the bride's family came to know his illness. So Otta Rosa decided to get married with Kattaalai...