"Sikkal" Shanmugasundaram is a devoted nadaswaram player, but is short-tempered and sensitive. He meets Mohanambal, a Bharatanatyam dancer, and they fall in love with each other. Sundaram's ego prevents him from developing his relationship with Mohana, who asks him to play a Thillana on his nadaswaram while she dances. Mohana's mother Vadivambal, an influential but greedy woman, wants her daughter to marry a wealthy man so that she can settle down in life properly. Blinded by love, she disobeys Vadivambal, creating a rift between them.

Unaware of Mohana's feelings, Sundaram decides to leave the country along with Karuppayi, a folk dancer whom he considers to be his sister. Mohana calls him a coward and challenges him to stay, which he readily accepts. In a temple, Sundaram plays the Thillana and Mohana dances. Sundaram, impressed with Mohana's performance, bestows upon her the title of "Thillana Mohanambal". Suddenly Nagalingam, a landlord who wanted to marry Mohana, stabs Sundaram with a poisoned knife out of jealousy.

Sundaram is admitted to a hospital but recovers from the incident with the help of Mary, a nurse who works there. Later, he and Mohana meet in a concert programme where they perform, against Vadivambal's wishes. For his personal gains, "Savadal" Vaithi, a cunning man, befriends the Maharaja of Madhanpur, who is the programme's chief guest. Vaithi promises to make Mohana the Maharaja's mistress. Vaithi traps Mohana by telling her that the Maharaja has invited nadaswaram and Bharatanatyam performers to perform in his palace, and that Sundaram has also decided to attend. Mohana immediately accepts the offer and the two visit Madhanpur. Vaithi treats Sundaram's group badly and Sundaram decides to leave. He sees Mohana visiting the Maharaja's room.

The Maharaja asks Mohana to be his mistress. but she rejects his advances and is rescued by the Maharaja's wife, the Maharani. Sundaram decides that Mohana does not love him, despite her repeated denial of the Maharaja's offer. Depressed, Mohana runs away. The Maharaja reveals the truth to Sundaram that Mohana had refused his offer and she only loves Sundaram. Realising his mistake, Sundaram rushes to apologise to Mohana, but sees her trying to hang herself from the ceiling of a room in which she had locked herself. He screams to her to stop and promises he will never doubt her love again. Sundaram breaks the door and saves Mohana. They then get married with Vadivambal's approval. Vaithi is arrested for his crimes.