Two Englishwomen, the young Miss Adela Quested and the elderly Mrs. Moore, travel to India. Adela expects to become engaged to Mrs. Moore’s son, Ronny, a British magistrate in the Indian city of Chandrapore. Adela and Mrs. Moore each hope to see the real India during their visit, rather than cultural institutions imported by the British.
At the same time, Aziz, a young Muslim doctor in India, is increasingly frustrated by the poor treatment he receives at the hands of the English. Aziz is especially annoyed with Major Callendar, the civil surgeon, who has a tendency to summon Aziz for frivolous reasons in the middle of dinner. Aziz and two of his educated friends, Hamidullah and Mahmoud Ali, hold a lively conversation about whether or not an Indian can be friends with an Englishman in India. That night, Mrs. Moore and Aziz happen to run into each other while exploring a local mosque, and the two become friendly. Aziz is moved and surprised that an English person would treat him like a friend.
Mr. Turton, the collector who governs Chandrapore, hosts a party so that Adela and Mrs. Moore may have the opportunity to meet some of the more prominent and wealthy Indians in the city. At the event, which proves to be rather awkward, Adela meets Cyril Fielding, the principal of the government college in Chandrapore. Fielding, impressed with Adela’s open friendliness to the Indians, invites her and Mrs. Moore to tea with him and the Hindu professor Godbole. At Adela’s request, Fielding invites Aziz to tea as well.
At the tea, Aziz and Fielding immediately become friendly, and the afternoon is overwhelmingly pleasant until Ronny Heaslop arrives and rudely interrupts the party. Later that evening, Adela tells Ronny that she has decided not to marry him. But that night, the two are in a car accident together, and the excitement of the event causes Adela to change her mind about the marriage.
Not long afterward, Aziz organizes an expedition to the nearby Marabar Caves for those who attended Fielding’s tea. Fielding and Professor Godbole miss the train to Marabar, so Aziz continues on alone with the two ladies, Adela and Mrs. Moore. Inside one of the caves, Mrs. Moore is unnerved by the enclosed space, which is crowded with Aziz’s retinue, and by the uncanny echo that seems to translate every sound she makes into the noise “boum.”
Aziz, Adela, and a guide go on to the higher caves while Mrs. Moore waits below. Adela, suddenly realizing that she does not love Ronny, asks Aziz whether he has more than one wife—a question he considers offensive. Aziz storms off into a cave, and when he returns, Adela is gone. Aziz scolds the guide for losing Adela, and the guide runs away. Aziz finds Adela’s broken field glasses and heads down the hill. Back at the picnic site, Aziz finds Fielding waiting for him. Aziz is unconcerned to learn that Adela has hastily taken a car back to Chandrapore, as he is overjoyed to see Fielding. Back in Chandrapore, however, Aziz is unexpectedly arrested. He is charged with attempting to rape Adela Quested while she was in the caves, a charge based on a claim Adela herself has made.
Fielding, believing Aziz to be innocent, angers all of British India by joining the Indians in Aziz’s defense. In the weeks before the trial, the racial tensions between the Indians and the English flare up considerably. Mrs. Moore is distracted and miserable because of her memory of the echo in the cave and because of her impatience with the upcoming trial. Adela is emotional and ill; she too seems to suffer from an echo in her mind. Ronny is fed up with Mrs. Moore’s lack of support for Adela, and it is agreed that Mrs. Moore will return to England earlier than planned. Mrs. Moore dies on the voyage back to England, but not before she realizes that there is no “real India”—but rather a complex multitude of different Indias.
At Aziz’s trial, Adela, under oath, is questioned about what happened in the caves. Shockingly, she declares that she has made a mistake: Aziz is not the person or thing that attacked her in the cave. Aziz is set free, and Fielding escorts Adela to the Government College, where she spends the next several weeks. Fielding begins to respect Adela, recognizing her bravery in standing against her peers to pronounce Aziz innocent. Ronny breaks off his engagement to Adela, and she returns to England.
Aziz, however, is angry that Fielding would befriend Adela after she nearly ruined Aziz’s life, and the friendship between the two men suffers as a consequence. Then Fielding sails for a visit to England. Aziz declares that he is done with the English and that he intends to move to a place where he will not have to encounter them.
Two years later, Aziz has become the chief doctor to the Rajah of Mau, a Hindu region several hundred miles from Chandrapore. He has heard that Fielding married Adela shortly after returning to England. Aziz now virulently hates all English people. One day, walking through an old temple with his three children, he encounters Fielding and his brother in law. Aziz is surprised to learn that the brother-in-law’s name is Ralph Moore; it turns out that Fielding married not Adela Quested, but Stella Moore, Mrs. Moore’s daughter from her second marriage.
Aziz befriends Ralph. After he accidentally runs his rowboat into Fielding’s, Aziz renews his friendship with Fielding as well. The two men go for a final ride together before Fielding leaves, during which Aziz tells Fielding that once the English are out of India, the two will be able to be friends. Fielding asks why they cannot be friends now, when they both want to be, but the sky and the earth seem to say “No, not yet. . . . No, not there.”