Mohan Bhargava (Shah Rukh Khan) is a non-resident Indian working as a project manager at NASA. He had been a student at the University of Pennsylvania, an Ivy League school. After the death of his parents and 12 years in the US, he decides to return to his hometown, Delhi, in India to find his nanny, Kaveri Amma (Kishori Ballal), with whom he has lost touch. After visiting the old-age home where Kaveri Amma resided, he finds out through her friend that Kaveri Amma was taken to a village Charanpur.
While there, he meets interesting people; there is the village postmaster, eager to know more about e-mail 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 is a cook who harbors ambitions of opening a dhaba on a US freeway and sees in Mohan an opportunity to get a visa.
While Mohan soon adapts to life in the village and endears himself to its people, he develops a cat-and-mouse romance with his childhood acquaintance Gita (Gayatri Joshi), who brought Kaveri Amma from the old-age home to be with her and her brother, Chiku (Master Smit Sheth). Gradually he encounters some of the harsher aspects of the village; among them are poverty, caste discrimination, child marriage, illiteracy, child labor, a general disregard for education, and 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, who runs the local school.
One day Kaveri Amma sends him to a village called Kodi to collect dues from a farmer named Haridas who has rented Gita’s land. Along the way, 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 would not support his attempts at a change of occupation from weaving to farming. Mohan returns empty handed but has a new sensitivity and perspective towards the harsh realities of rural India. This journey to Kodi and back proves to be the turning point in Mohan’s life, and he comes back with a resolve to improve 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 is time for him to leave as his project at NASA is nearing 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 and who had fallen in love with him, 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 finishes his project at NASA before resigning and returning to India. The movie ends with Mohan and the postmaster wrestling for fun. Mohan wins.