Miss Lucy Honeychurch is a somewhat naïve young woman sent on holiday to Italy under the charge of her older cousin, Miss Charlotte Bartlett. The two are staying at the Bertolini Pension in Florence. The story opens around the dinner table at the pension, where Lucy and her cousin lament that though promised rooms in the front of the pension, they have been given rooms in the back, with no view. One of the other guests, Mr. Emerson, offers to switch rooms with them, as he and his son George, a quiet young man, have a view from their two rooms. However, his generous offer is viewed with suspicion by the other pension guests, just as his abrupt and open manner offends their own "upper class" notions of tactful behavior. Charlotte refuses the offer.
Mr. Beebe, a clergyman who once worked in Lucy's parish and will be returning there in a few months, makes a surprise appearance. He is now vacationing at the pension, which excites and pleases Lucy. He intercedes in order to help the Emersons save face, and the two parties do switch rooms. Affixed to the wall in George Emerson's former room, Charlotte finds a large question mark drawn on a piece of paper.
The next day, Lucy goes out for a first look at Florence, under the guidance of another pension guest, the "clever," energetic Miss Eleanor Lavish. Lavish, a writer, claims she can show Lucy "the true Italy," and takes away her copy of Baedeker's guidebook. After losing their way, they finally reach Santa Croce church, where Lucy's companion becomes distracted by an acquaintance and abandons her. However, Lucy finds the two Emersons inside the church, and the three admire the fine Giotto frescoes and carved tombstones. The Rev. Cuthbert Eager is leading a tour through the church and Mr. Emerson offends him by loudly criticizing his lecture on Giotto's frescoes. Alone together, George speaks to Lucy about his father's frank manner of speaking and how it offends everyone despite his good intentions. Then Mr. Emerson and Lucy walk together and he explains his son's mysterious melancholy, saying that George's trouble is that he is distressed that the "things of the universe...don't fit." He asks Lucy to make George realize "that there is a Yes," a joyfulness in the world itself. Then Charlotte arrives on the scene and whisks her unescorted cousin away.
Lucy plays the piano at the pension on a rainy afternoon, while Miss Catharine Alan, an old wealthy woman, and Mr. Beebe discuss the other guests, particularly the Emersons, who have fallen out of nearly everyone's favor. Miss Catharine decides that they are "not nice," and points out, "they don't understand our ways. They must find their level." Lucy says that she thinks the Emersons are nice. The rain has cleared, and Lucy, on a rebellious impulse, decides to go outside, wanting to take the circular electric tram. Her elders disapprove of the notion, and she sadly agrees to walk.
Walking in Florence, Lucy feels discontented and dull, thinking that "nothing ever happens to me." She buys some photographs of Italian artworks. Suddenly, as she enters the Piazza Signoria, she comes near two Italians bickering about a debt. As one turns toward her, blood pours from his mouth while the other stabs him in the back. Lucy faints, seeing George out of the corner of her eye as she falls. She awakes next to him on the steps nearby, apologizing for herself. George insists on walking her to the pension; Lucy tries to evade him while he collects her fallen postcards. He commands her to wait, and they walk back together. He suddenly throws the postcards into the River Arno, explaining upon rigorous questioning that they were covered in blood. Lucy, fearing gossip and disapproval, asks George not to tell anyone about her "foolish behavior" (fainting and being caught in his arms). As they gaze down to the roaring river, Lucy sums up their experience saying, "How quickly these accidents do happen, and then one returns to the old life." George simply says mysteriously, "I shall probably want to live."
Forster's book presents detailed analyses of and commentary on the social mores and tensions of his day. The opening chapters are mostly concerned with his masterful fleshing out of a cast of characters. The pension guests are culled from the "better class of tourist." That is, they come from wealthy, supposedly better-educated families of good breeding and social standing. They identify themselves through polite, genteel conventions of speech and manners and accept and reject all others based on their accordance with these and other standards.