Lord Mountbatten arrives at Viceroy's House in Delhi in 1947 with his strong-willed wife Edwina and daughter Pamela. As the final Viceroy of India, he is in charge of overseeing the dissolution of the British Raj and the establishment of an independent Indian nation. Mountbatten attempts to mediate a disagreement between the two major Indian political leaders, Jawaharlal Nehru, who wants India to remain intact as one nation after independence, and Muhammad Ali Jinnah, who wishes to establish the separate Muslim state of Pakistan.

Meanwhile, Mountbatten's newly-arrived valet Jeet encounters the beautiful Alia, whom he had fallen in love with previously. Alia continues to spurn Jeet because he is Hindu and she Muslim; she fears that she will disappoint her invalid father Ali.

With riots erupting across India, the British decide to accelerate the independence process. Mountbatten is intent upon a one-state solution, but with intensifying violence between Muslims and Hindus he reluctantly accepts the Partition of India. He is given only a couple months to carve out a separate state from the existing territory, with the help of an inexperienced English lawyer. Jeet continues to pursue Alia until it is revealed that she has been betrothed since childhood to another man. The servants at Viceroy House are forced to choose between staying in India or going to Pakistan.

Louis is enraged to find that his Chief of Staff Lord Ismay, has been working covertly to draw the boundaries of Pakistan in order to create a buffer state between the Indian subcontinent and the Soviet Union. He realizes that he has been used as a pawn and the displacement of millions of people will result. Jeet is devastated to learn meanwhile that his entire family have been slaughtered in the Punjab. Although Alia rejects her fiancé when he returns to claim her, she chooses to depart for Pakistan with her father. Days later Jeet reads in the newspaper that the night train she had boarded was attacked and everyone was killed. In anger he brandishes a knife at Mountbatten, before resigning his post.

With Delhi overwhelmed with refugees, the Mountbattens decide to stay on in India to assist where they can. While Jeet volunteers to help with the refugees, Alia is brought in badly injured but alive, the lone survivor of the train attack. She recognizes Jeet and shouts for him, and the two are reunited.