Anu is a dancer in love with Bharani, a flautist. After her father is transferred to Bombay, she slowly loses touch with Bharani, who does not respond to her letters. When her father falls ill, his colleague Ramanathan supports them. When Ramanathan offers to marry Anu, she is in a fix. She seeks time to decide and writes one last letter to Bharani; due to no reply, she marries Ramanathan. Soon after, her father dies.

After marriage, Ramanathan reveals his true personality; chauvinistic, sadistic and possessive. Not wanting to be identified as a dancer's husband, he forces her to give up dancing. Ramanathan suspects Anu's character and expresses doubts regarding the paternity of their newborn son. Unable to take further abuse, and also for the well-being of her son, she divorces Ramanathan, refuses alimony, and returns to Madras to start a new independent life.

In Madras, Anu gets supportive friends at her office, particularly a widower Janardhan "Johnny" who frequently "talks" through his puppet, Junior. As Anu struggles to find a house, he offers his own flat and moves to his outhouse. Despite loving Anu, he lacks the courage to tell her. Bharani, Johnny's neighbour, visits and is surprised to see Anu. She learns that none of her letters had reached Bharani, since they were intercepted by his mentally-ill sister. Bharani saw the letters only after his sister died. By then it was too late as Anu had already married Ramanathan. Heartbroken, Bharani remained single.

Ramanathan's estranged mother Leelavathi realises Anu is her daughter-in-law. She regrets her son's behaviour; exploiting her anonymity, she obtains work as Anu's maid. Anu renews her relationship with Bharani. Leelavathi also supports Anu's decisions and advises her to move ahead in life. They decide to marry and a date is fixed for a civil wedding.

Ramanathan comes to Madras as Anu's boss, seemingly repentant and wanting to redress his wrongs. He does not reveal that he is Anu's ex-husband to Bharani, who reveals his plans to marry Anu. Johnny learns about Anu and Bharani's love; though disappointed, he continues to support Anu. Leelavathi convinces Anu to discard her mangala sutra and marry Bharani. But on the scheduled day, Anu falls ill and does not turn up at the marriage registrar's office. Bharani comes to her house, where he is disappointed to see Ramanathan taking care of Anu. Three men — Ramanathan, Bharani and Johnny — vy for her.

Ramanathan seeks forgiveness and expresses his desire to re-marry Anu. When Anu's colleague Rajathi, who knows Leelavathi, visits Anu, she is stunned to see Leelavathi employed as her maid. Despite Leelavathi's earlier pleas not to reveal her identity, Rajathi does so out of frustration. Shocked, Anu seeks Leelavathi's forgiveness. She goes to meet Johnny to seek his advice. Johnny finally courageously reveals his love for Anu through Junior. Anu expresses her inability to accept his love, but seeks his continued support as a friend. Noticing Anu's predicament and Ramanathan's continued involvement in her life, Bharani decides to move away from her and goes abroad for his musical programmes.

Ramanathan's reformed behaviour and Leelavathi's sacrifices make Anu agree to become Ramanathan's wife once again. When she reaches his home, Leelavathi reveals that Ramanathan has not really changed; he had staged this drama to stop her marriage to Bharani. When another woman shows up with her child claiming to be Ramanathan's wife, Anu realises Ramanathan's hidden agenda. Anu rushes to meet Bharani, but is too late by then, as Ramanathan has convinced Bharani to marry his rich fan Gayathri, and the engagement takes place.

Anu confronts Ramanathan; he reveals that he could not tolerate his ex-wife living happily, hence he ensured that all her dreams are shattered. Anu quits her job and plans to leave Madras. Johnny makes all arrangements for her travel to Trivandrum, her destination. When the train leaves, Anu is shocked to see Leelavathi also onboard. Leelavathi says this is the only way she can find solace for the sins of her son. Anu and Leelavathi embrace.