"Saappattu" Raman is a bumpkin living in the village Poongudi. Having lost his parents in his childhood, he was raised by his grandmother. One day Raman gets a seizure, falls into the village tank and almost drowns until a woman named Devaki, who was informed by a witness, saves him. Devaki is the younger sister of Minor Rajarathnam, a zamindar and the richest man in the village, and has just returned from Madras. Raman becomes infatuated with Devaki, who only feels affection for him because of his childish nature, which others misinterpret as love.

At night, Raman breaks into Devaki's bedroom and declares his love for her; to prove it, he jumps out of the window and survives the fall, only breaking a leg. After recovering, he visits Rajarathnam and requests him for permission to marry Devaki. Rajarathnam humiliates and beats Raman up, citing the fact that there are millionaire suitors for Devaki whereas Raman is poor. In response, Raman vows to become rich and marry Devaki. He then leaves to Madras looking for his fortune.

In Madras, Raman struggles to earn money while doing menial jobs. He meets his best friend Mookurinji, now a film actor known as Gopi. With his help, Raman joins the film industry. At a shooting spot a writer is looking for someone to recite a dialogue. When no one volunteers, Raman jumps in and tries to impress the writer. His recitation does not impress the writer, but his enthusiasm and spirit wins the director's favour. He soon becomes a successful movie star known as Vijayakumar.

Raman returns to Poongudi, dreaming to marry Devaki, but is shattered upon learning that she was forced to marry Muthu, a rich man, under compulsion from her brother. Heartbroken, he returns to Madras. A few days later, he finds Devaki and she tells him about the cowardly Muthu and that she left him. The reason being that after ill-treating her, he took her to a party. There his friend Balu tried to rape her and threatened to shoot anyone trying to stop him. Muthu fled for his life, forcing Devaki to knock Balu out with a vase. After hearing this, Raman offers to take care of her which she refuses.

Balu again tries to rape Devaki, who kills him this time. Devaki runs to Raman and gives him her baby daughter Sumathi to take care of her while she surrenders to the police. Using his influence, Raman helps Devaki receive a reduced sentence of five years. Meanwhile Raman brings up and educates Sumathi. Having squandered his wealth, Muthu becomes the school bus driver of Sumathi and Sumathi realises he is missing his wife. She meets his wife (her mother) at jail coincidentally. Raman is with Sumathi during this meeting but Devaki stops him from speaking. Completing her jail sentence, Devaki becomes a teacher in a small school letting Raman know of her whereabouts.

Time moves on as Sumathi goes to college, being brought up as a well mannered girl by Raman. She then falls in love with Gopi. Raman agrees to their marriage. He informs Devaki and requests her presence. When he brings Devaki home, Sumathi is absent as she has gone to a party. Raman rushes to the party and finds an attempt to rape Sumathi taking place. He fights the rapist but an attack by the rapist triggers a seizure, due to which Raman loses control and accidentally kills him. Sumathi saves Raman and brings him home by taxi. But Raman calls the police to surrender. He also reunites Muthu, who drove the taxi, with his family.