Raman or Ramu (Sivaji Ganesan) is an orphan who is a foodie and wins all the eating competitions and is fondly called 'Sappattu Raman' (Food Lover) in the Poongodi village. He frequently gets epileptic seizures.
The rich 'Minor' Rajarathinam (M.N. Nambiar) dominates the village. His only sister Devaki (K.R. Vijaya) returns from the city and a young boy seek her help when Ramu gets seizures and Ramu likes her helpfulness.
Devaki visits the temple and Muthu (R. Muthuraman) accidentally dashes her. He apologizes but her driver informs this to Rajarathinam who calls Muthu's host and whips him. Muthu swears revenge and leaves.
One day Devaki takes shelter at Ramu's house when it rains. She enjoys her time there and playfully winks at him. His young friends mistake it as love and tell Ramu to reciprocate. He goes to her house one night and reciprocates. To prove his love he jumps down and breaks his legs and she understands his true affection.
Ramu recovers and on his friends' suggestion goes and expresses his desire to Rajarathinam to marry Devaki, who insults and whips him. Ramu cries out in pain and demands to know the eligibility to marry Devaki and Rajarathinam asks him to earn Rs. 1 Lakh and come back. Ramu challenges him and goes out. Devaki promises Ramu that she will wait for him.
Ramu reaches Chennai and meets Gopi (Master Prabhakar), who was his friend at the village and is now working in a film shooting unit. Ramu talks about his ability to tell dialogues well and gets noticed by a big director (V. Nagaiah) who gives him a chance. His film runs well and all his film starts doing well. His screen name is Vijayakumar and he becomes a big star and earns millions in a few years. Now Ramu decides to visit the village to seek Devaki's hand.
Ramu as Vijayakumar reaches the village and reveals to Rajarathinam that he is none other than Ramu. He brings lakhs of rupees and offers to Rajarathinam and asks for Devaki's hand. Rajarathinam is shocked and informs him that Devaki is already married. Ramu is disturbed and leaves.
One day in Chennai, he recognizes Devaki at a bus stand. He follows her and after much persuasion, she reveals the facts: Muthu from a rich family sought her hand and Rajarathinam agreed without her consent. After marriage, Muthu started treating her badly as he assumed that it was she, who had complained to her brother. At his friend Balu's (S.V. Ramadas) birthday party, he forced her to sing. When Muthu was in an inebriated condition Balu tried to molest her. Muthu came to rescue her but when Balu shot him, he ran away. Finally, Devaki hit Balu on his head and escaped from there. Devaki walked out of her marriage as she was not keen to live with a coward. She was pregnant then and later delivered a baby girl. Ramu is shocked and tells her to come and live with him but she refuses.
Within a few days, Balu finds Devaki's but and tries to molest her again and this time she kills him. She meets and requests Ramu to bring up her child and then she surrenders to the Police. She is awarded 5 years in jail term at Vellore.
Ramu does not get married and dedicates his life to bring up the child. Five years pass by and the child Sumathi (Baby Rani) is a smart girl. He keeps meeting Devaki at the Vellore jail and updates her on Sumathi's progress. Meanwhile, Muthu loses all his wealth and works as a school bus driver and takes Sumathi in his bus. One day he loses his license and she finds it and notices a photograph of him with a lady. Ramu and Sumathi visit Vellore jail for a cultural program and Devaki meets Sumathi but does not reveal her identity. But Sumathi says that she has seen Devaki's photo with the school van driver. On the day of her release, Ramu goes to meet Devaki at the jail but gets only her letter. She informs that she does not want to spoil Sumathi's future by presenting herself as the child's mother.
Fifteen years pass by. Sumathi is a beautiful young girl studying in college. Gopi (Sudheer), Ramu's assistant, and Sumathi like each other, and Ramu approves their marriage. However, he says that one more person has to accept it and he keeps it as suspense. Ramu then goes to meet Devaki, convinces her, and brings her home. By then, Sumathi goes to attend a birthday party where a rogue tries to molest her. Ramu, comes to know about her outing, reaches in time there, beats the rogue, and saves her. But the rogue hits him with a vase and Ramu gets epilepsy and unknowingly, hits the rogue on a wall which has a nail at that spot and he dies. Ramu recovers from the seizure and is shocked to see the death. Sumathi's car does not start and she takes the help of a taxi driven by Muthu. Muthu notices Ramu and Sumathi and recognizes her. Ramu now understands that Muthu is Sumathi's father and decides to unite them.
They reach home and Ramu introduces Devaki to Sumathi as her mother. He says he has killed someone and hands over Sumathi to Devaki. Muthu apologizes and Ramu pleads with Devaki to accept Muthu who is now reformed and she accepts. Ramu transfers all his wealth to Sumathi and then surrenders to the Police.
[from the book Pride of Tamil Cinema: 1931 to 2013 by G Dhananjayan, Blue Ocean Publishers, 2014]