It's 1919, and the narrator, W. Somerset Maugham, is in Chicago. An old friend, Elliott Templeton, an American living in Paris (and a great snob) who happens to be in town, invites him to lunch with his sister. Also present at the luncheon are Mrs. Bradley's daughter, Isabel, along with her friend Laurence Darrell. At a subsequent dinner, Maugham meets more of Isabel's set — namely Gray Maturin and Sophie. Larry's future is of much interest to everybody. After having returned from the war (WWI), Larry did not to go to college. He refuses a job from friend Gray Maturin's stockbroker father.
Isabel loves Larry and agrees to wait for him for a couple years while he goes to Paris to "loaf."
Maugham relates to the reader what he learned many years later concerning Larry's time in the war. He'd watched a great friend of his die, from injuries suffered while saving Larry's hide in a dogfight.
Larry wants no part of Elliott's Paris. He lives in a room in the Latin Quarter and reads a lot. Isabel when she sees how Larry lives breaks off their engagement. However, they continue to see quite a lot of each other. Elliott and Mrs. Bradley conspire to take her away to London, to improve her chances for marriage with other boys.
Isabel has a tête-à-tête with Maugham, who thinks it's pretty clear that Larry is seeking God. Isabel confesses she'd planned to seduce Larry, to trick him into marrying her. There's no doubt that she loves him — or wants him — but she doesn't understand him.
Larry decides he needs a rest from books and goes to work in a coal mine in Lens, in the north of France. He befriends a former Polish army officer, who is an unwitting spiritual guide. Together they travel through Belgium and Germany. Larry sets off for Bonn on his own. (Maugham would only learn the details of all this 10 years hence.)
Isabel marries Gray Maturin. They have two daughters, and live in style, in Chicago.
Elliott's standing in society is slipping, and he doesn't care for the ways of the newer generation. He buys a house on the Riviera. And then the stock market crashes.
Gray's father is financially ruined and dies of coronary thrombosis. Gray and Isabel sell most of their properties and her jewels. The Riviera is in a bit of a slump, but Elliott is settling in nicely. Gray can't get work. When Mrs. Bradley's health takes a turn for the worse, Elliott goes to Chicago, and sees for himself that Isabel and Gray "live like pigs." Mrs. Bradley dies. Elliott brings Isabel and Gray over to live in his Paris apartment.
Maugham is in the habit of seeing Isabel a few times a week for a gossip. Quite by chance he meets Larry at a café. Larry is just returned from India and looks like a tramp. A few days later he stops by Isabel's place. Larry's tells them a bit about his time in India — he stayed in an ashram with Yogis. He read, walked, meditated. When they meet for supper the next day, Larry uses hypnotism to cure Gray of a migraine.
Isabel, Gray, Larry, and Maugham spend quite a bit of time together. One night, Isabel proposes a tour of "the tough joints" around Paris. In a dingy place in the Rue de Lappe they meet Sophie, drunk and doped and slutty. Maugham recalls having met her years before in Chicago. Sophie had married and had a baby, but husband and child had been killed in a car accident. She'd gone crazy with grief and turned to drink. Isabel says she's plain evil. Larry reveals that he and Sophie had been close friends as teenagers, with a shared interest in poetry.
The summer passes. Larry is going to marry Sophie. Maugham surmises that Larry hopes to save her. Everyone goes out to dinner and drinks Żubrówka. Isabel invites Sophie to a dress show.
They arrange to meet again for a final fitting. Sophie waits, then leaves, and no one sees her again.
A year later, Maugham would find her on the Riviera, more or less returned to her old ways. Sophie tells him Isabel had left a bottle of Żubrówka out, and finally she gave in to temptation. Once drunk, she ran away.
Elliott's health is failing. He is miserable for not having been invited to a certain princess's fancy-dress party. Maugham steals an invitation to post to Elliot. The bishop himself administers last rites to Elliott. Elliott sends his regrets that he cannot attend the party "owing to a previous engagement with his Blessed Lord." And he dies.
Maugham warns the reader that this section can be skipped without losing the thread of the story, but were it not for the events he recounts here, he would not have written this book.
The police call on Maugham with regard to Sophie. Her body was fished out the harbour, her throat cut. In her apartment they found a book Maugham had inscribed to her, along with a few volumes of poetry, and a photo of Larry.
Larry leaves for America. Isabel and Maugham receive copies of his book. It's a collection of essays, on Sulla, the Roman dictator; Akbar, the Mogul conqueror, Rubens; Goethe, and Lord Chesterfield.
Maugham confronts Isabel for deliberately setting temptation in Sophie's way, for as good as killing her herself.
Isabel and Gray have plans to return to America themselves, to Texas; it's quite clear this is not Larry's America.
"Elliott social eminence; Isabel an assured position; ... Sophie death; and Larry happiness."