The film revolves around Ammu (Bharathi), an orphan brought up in a prostitute's house. Brought up in such atmosphere, she develops a fascination for the world's oldest profession. She comes across a writer Gowrishankar (R. Parthiepan), who comes to her place to pen a novel on the life of a commercial sex worker. Her childlike innocence wins over Gowrishankar's heart. He decides to marry her. Gowrishankar's love and care brings a change in Ammu. She understands the value of family and the bond of togetherness. Gowrishankar completes his novel Ammuvagya Naan and hopes for a national award for it. Fate pays a cruel act in the form of a president of a literary association (Mahadevan). He bargains for a night with Ammu to ensure the national award for Amuvagiya Naan. Eventually, Ammu kills the president.