| Director | Benny Chan, S. J. Surya |
|---|
Eight-year-old Pappu always troubles his mother Indira and frequently gets scoldings due to his bed-wetting. Pappu's elder brother Kishore plans to watch a porno with his friends in his room. Pappu insists on joining them. When Kishore refuses and gets rid of him, Pappu cuts off the power out of anger, creating a short circuit at home. Indira scolds Pappu and shouts at her husband for not stopping with one child. Distraught, Pappu leaves to end his life near a river, but is stopped by a man who takes him to his home. The man is a scientist who has his own laboratory. He convinces Pappu to take a medicine invented by him which will transform a boy into a fully-grown man. Pappu agrees and turns into a young man. However, he still has the mind of a child. The only person other than the scientist who knows the truth is Pappu's classmate and friend, Deepak.
Now an adult, Pappu goes for an interview in a toy manufacturing company under the name of Vichu. The owner interviewing him demands that he empathise with children to understand their taste. Since Vichu is a child, he gets the job easily. He meets the owner's daughter Priya, whom Vichu helped to her feet at an amusement park earlier. The two fall in love. Their intimacy makes Raj, another employee enamored with Priya, jealous. Vichu eventually learns that his mother is depressed and sick following Pappu's disappearance. She laments for being so strict with him. After learning of her love for him, Vichu asks the scientist to revert him to his eight-year-old self. The scientist transforms Vichu into Pappu, who reconciles with his mother. However, at night, he turns back to Vichu, and rushes to the scientist, who does not know what went wrong.
Pappu now lives as an eight-year-old boy during daytime and as a 28-year-old Vichu during the night. Priya expresses her love to him. Vichu tells her to love a man suitable for her age, but he reciprocates her love upon the scientist's coercion. One day, Priya asks him to accompany her to a matinee show, to which he rejects so she does not find out what is actually going on. Pappu's mother befriends Priya as they are neighbours. Priya likes Pappu, but is angered by Vichu's absence. After angrily hitting Vichu, she decides to marry him. Raj gets Vichu kidnapped on the day of marriage, but he changes to Pappu during the day. The kidnappers release him, thinking that they kidnapped a child by mistake. Pappu turns into Vichu and marries Priya that evening. Priya longs for a child, so they eventually have sex, which results in her becoming pregnant. Vichu/Pappu meets his mother and understands the difficulties of pregnancy, prompting him to take care of Priya with more affection.
Deepak demands ice cream but Vichu refuses, having a tight schedule as a son, employee, and husband. Deepak gets angry and reveals to Priya that Vichu is Pappu. She is shocked that she is bearing the baby of a child. Priya blames Pappu for ruining her life and making her pregnant, during which he transforms to Vichu. He gets angry and blames her for everything. He reveals that he started to love her when she got pregnant and saw his mother in her. Priya goes into labour and Vichu takes her to the hospital. En route, Vichu is stopped by Raj and his men, who seek revenge. Vichu fights them and admits her in a hospital. There, everyone learns the truth about Pappu, and Priya gives birth to his son while being upset on her fate of being a child's wife.
Twenty years pass later, Pappu is an actual 28-year-old. He still is Priya's husband. He goes inside his room as a young man and comes out as the 48-year-old Vichu. His son is a 20-year-old who looks like him. Vichu contacts the scientist to see if he found a remedy for his transformation. The scientist replies that he did not.