Mohan Bhargava (Shahrukh Khan) is an NRI working at NASA in a lucrative and prestigious position. He had been a student at the University of Pennsylvania, an Ivy League school with a large Asian population. After twelve years in the US, he decides to return to India to find his nanny, Kaveri Amma, with whom he has completely lost touch. Along the way, he meets a number of interesting people from the village called Charanpur where Kaveri Amma now lives; there's the village postmaster, eager to know more about e-mails and the internet, while also having a keen hobby of wrestling; the ex-freedom fighter who teaches history at the local school and is a lone voice of reason amongst the village elders; there's also a cook who harbours ambitions of opening a dhaba on a US freeway, and sees in Mohan an opportunity to get himself a visa.
While Mohan soon adapts himself to life in the village and endears himself to its people, he also encounters some of its harsher aspects. Among them are poverty, caste discrimination, child marriage, illiteracy, a general disregard for education and an apathy to change. He tries in his own way to bring about some change, even succeeding to the point of dissuading the village elders from moving the local school to smaller and far-away premises. In doing this, he earns the respect of Gita (Gayatri Joshi), a childhood acquaintance who lives with Kaveri Amma and runs the local school.
One day Kaveri Amma sends him away to another village called Kodi to collect dues from a farmer named Haridas who has rented their land. Along the journey, Mohan realizes that the problems he had seen in the village mirror those faced by almost all other villages in the country. Haridas, the farmer who owes rent has no money to feed his own family, mainly because the villagers wouldn't support his attempts at a change of occupation from weaving to farming. Mohan returns empty-handed but resolves to take more interest in improving the quality of life of the villagers.
He enlists the support of a few hundred men and guides them through the building of a reservoir beneath a perennial spring on a nearby hill. Buying turbines and other equipment with his own money, he sets up a small hydro-electric power plant that would solve the problem of irregular electricity and make the village self-sufficient.
By then, it's time for him to leave as his project at NASA is near its final stage. Kaveri Amma, whom he had intended to take along with him, refuses to come citing the difficulty of adapting to a new culture at such a late stage in her life. Gita, whom he had fallen in love with, also refuses to come with him, wanting to remain in the country and continue running the school that her parents had founded. He returns alone but feels a growing sense of responsibility towards his country and guilt for not being able to do much for the welfare of its people. He, nevertheless, stays to finish his project at NASA before resigning and returning to India.