The first part of the novel is set in Florence, Italy, and describes a young English woman's first visit to Florence, at a time when upper middle class English women were starting to lead independent, adventurous lives. Lucy Honeychurch is touring Italy with her overbearing older cousin and chaperone, Charlotte Bartlett, and the novel opens with their complaints about the hotel, "The Pension Bertolini." Their primary concern is that although rooms with a view of the River Arno have been promised for each of them, their rooms instead look over a courtyard. A Mr. Emerson interrupts their "peevish wrangling," offering to swap rooms as he and his son, George Emerson, look over the Arno. This behaviour causes Miss Bartlett some consternation, as it appears impolite. Without letting Lucy speak, Miss Bartlett refuses the offer, looking down on the Emersons because of their unconventional behaviour and thinking it would place her under an "unseemly obligation" towards them. However, another guest at the pension, an Anglican clergyman named Mr. Beebe, persuades the pair to accept the offer, assuring Miss Bartlett that Mr. Emerson only meant to be kind.
The next day, Lucy embarks on a tour of Florence with another guest, Miss Eleanor Lavish, a novelist who shows Lucy the back streets of Florence, takes her Baedeker guidebook and subsequently loses her in Santa Croce, where Lucy meets the Emersons again. Although their manners are awkward and they are deemed socially unacceptable by the other guests, Lucy likes them and continues to run into them in Florence. One afternoon Lucy witnesses a murder in Florence. George Emerson happens to be nearby and catches her when she faints. Lucy asks George to retrieve some photographs of hers that happen to be near the murder site. George, out of confusion, throws her photographs into the river because they were spotted with blood. Lucy observes how boyish George is. As they stop to look over the River Arno before making their way back to the hotel, they have an intimate conversation. After this, Lucy decides to avoid George, partly because she is confused by her feelings and partly to keep her cousin happy—Miss Bartlett is wary of the eccentric Emersons, particularly after a comment made by another clergyman, Mr. Eager, that Mr. Emerson "murdered his wife in the sight of God." Later on in the week, a party made up of Beebe, Eager, the Emersons, Miss Lavish, Miss Bartlett and Lucy Honeychurch make their way to Fiesole, in carriages driven by Italians. The driver is permitted to invite a woman he claims is his sister onto the box of the carriage, and when he kisses her, Mr. Eager promptly forces the lady to get off the carriage box. Mr. Emerson remarks how it is defeat rather than victory to part two people in love. In the fields, Lucy searches for Mr. Beebe, and asks in poor Italian for the driver to show her the way. Misunderstanding, he leads her to a field where George stands. George is overcome by Lucy's beauty among a field of violets and kisses her, but they are interrupted by Lucy's cousin, who is outraged. Lucy promises Miss Bartlett that she will not tell her mother of the "insult" George has paid her because Miss Bartlett fears she will be blamed. The two women leave for Rome the next day before Lucy is able to say goodbye to George.
In Rome, Lucy spends time with Cecil Vyse, whom she knew in England. Cecil proposes to Lucy twice in Italy; she rejects him both times. As Part Two begins, Lucy has returned to Surrey, England to her family home, Windy Corner. Cecil proposes yet again at Windy Corner, and this time she accepts. Cecil is a sophisticated and "superior" Londoner who is desirable in terms of rank and class, even though he despises country society; he is also somewhat of a comic figure in the novel, as he gives himself airs and is quite pretentious.
The vicar, Mr. Beebe, announces that new tenants have leased a local cottage; the new arrivals turn out to be the Emersons, who have been told of the available cottage at a chance meeting with Cecil; the young man brought them to the village as a comeuppance to the cottage's landlord, whom Cecil thinks to be a snob. Fate takes an ironic turn as Lucy's brother, Freddy, meets George and invites him to bathe in a nearby pond. Freddy, George and Mr Beebe go to the pond, in the woods, take off their clothes and swim. They enjoy themselves so much they end up running around the pond and through the bushes, until Lucy, her mother, and Cecil arrive, having taken a short-cut through the woods. Freddy later invites George to play tennis at Windy Corner. Although Lucy is initially mortified at the thought of facing both George and Cecil (who is also visiting Windy Corner that Sunday), she resolves to be gracious. Cecil annoys everyone by reading aloud from a light romance novel that contains a scene suspiciously reminiscent of when George kissed Lucy in Florence. George catches Lucy alone in the garden and kisses her again. Lucy realises that the novel is by Miss Lavish (the writer-acquaintance from Florence) and that Charlotte must thus have told her about the kiss.
Furious with Charlotte for betraying her secret, Lucy forces her cousin to watch as she tells George to leave and never return. George argues with her, saying that Cecil only sees her as an "object for the shelf" and will never love her enough to grant her independence, while George loves her for who she is. Lucy is moved but remains firm. Later that evening, after Cecil again rudely declines to play tennis, Lucy sours on Cecil and immediately breaks off her engagement. She decides to flee to Greece with acquaintances from her trip to Florence, but shortly before her departure she accidentally encounters Mr. Emerson senior. He is not aware that Lucy has broken her engagement with Cecil, and Lucy cannot lie to the old man. Mr. Emerson forces Lucy to admit out loud that she has been in love with his son George all along.
The novel ends in Florence, in melodramatic fashion, where George and Lucy have eloped without her mother's consent. Although Lucy "had alienated Windy Corner, perhaps for ever," the story ends with the promise of lifelong love for both her and George.
In some books, an appendix to the book is given entitled "A View without a Room," written by Forster in 1958 as to what occurred between Lucy and George after the events of the novel. It is Forster's afterthought of the novel, and he quite clearly states that "I cannot think where George and Lucy live." They were quite comfortable up until the end of the war, with Charlotte Bartlett leaving them all her money in her will, but World War I ruined their happiness according to Forster. George became a conscientous objector, lost his government job but was given non-combatant duties to avoid prison, leaving Mrs Honeychurch deeply upset with her son-in-law. Mr Emerson died during the course of the war, shortly after having an argument with the police about Lucy continuing to play Beethoven during the war. Eventually they had three children, two girls and a boy, and moved to Carshalton from Highgate to find a home. Despite their wanting to move into Windy Corner after the death of Mrs Honeychurch, Freddy sold the house to support his family as he was "an unsuccessful but prolific doctor."
After the outbreak of World War II, George immediately enlisted as he saw the need to stop Hitler and the Nazi regime, but was not faithful to Lucy during his time at war. Lucy was left homeless after her flat in Watford was bombed and the same happened to her married daughter in Nuneaton. George rose to the rank of corporal but was taken prisoner by the Italians in Africa. Once Italy fell George returned to Florence finding it "in a mess" but he was unable to find the Pension Bertolini, stating "the View was still there and that the room must be there, too, but could not be found." He ends by stating that George and Lucy await World War III, but with no word on where they live, for even he does not know.