The film starts with Tamil (Vimal) who is raised single-handedly by his grandfather, Venkatasamy (Rajkiran) in a village, as his parents had committed suicide after eloping and giving birth to him. 25 years later the boy is working in a Chennai-based IT company, staying in a modern upmarket apartment. Tamil meets Karthika (Lakshmi Menon), a medical student using tricks to get to the front of the traffic signal. They fall in love at first sight, and end up being so engrossed in each other that they don't realise that the signal had gone green. The way Karthika tricks the police officer and gets away with it endears Tamil to Karthika. He follows her and in no time she reciprocates.

Meanwhile, at work, Tamil is selected to go to US for a three-month project and he brings Venkatasamy to the city so that they can spend time together before he leaves for US. Venkatasamy, coming from a rustic background, is unfamiliar with the urban lifestyle of people in a modern city.

He bathes and washes his clothes at a fountain, causing much embarrassment to Tamil which he does not share with Venkatasamy. He causes further hardship by disturbing Tamil during his date with Karthika, causing a breakup between them. Venkatasamy infuriates Tamil further by slapping Karthika's father, an Inspector of Police, for allowing his daughter to wear short clothes in public. Tamil pleads with Karthika and finally she forgives him.

Tamil spends several nights working on a project on his laptop. Venkatasamy assumes the laptop to be a sandwich grill and without knowing how to use it, puts it on the stove causing the laptop to explode into pieces, destroying the project work. Tamil is sacked from his job as a result but hides his anger from Venkatasamy.

Karthika motivates Tamil to complete the project on her computer. The old man feels really guilty of destroying the laptop, and buys him a new one by selling his ancestral wedding ring. Tamil thanks his grandfather and starts working on the project. He finishes the project and gets his job back.

Meanwhile, the old man helps a couple elope and get them married the same way he did with Tamil's parents. While Tamil is leaving to attend an interview to go to the US, Venkatasamy mocks the US flag at the US consulate and thinks that the whites are conquering India again. He creates a nuisance and both of them are arrested. When they come out of the station, Tamil goes for a second interview but his visa is rejected; he scolds his grandfather amidst a large crowd.

A girl, Pooja (Yuvina Parthavi), thinks that a piece of sweet laced with rat poison is a sweet that the old man gave her and faints after eating it. She was brought to the hospital and the old man is scolded in public for the second time by the girl's parents. The girl is cured thanks to the mixture of salt and tamarind water Venkatasamy gave Pooja before she was taken to the hospital, helping her to vomit and get rid of the poison.

When everyone wants to apologise and thank the old man, he goes missing and everyone starts to search for him. The old man is finally located but in a mentally challenged state. The film ends with Tamil regretting scolding his grandfather and crying while hugging him tightly.[2]