The narrator is Jake Barnes, an American newspaperman in 1920s Paris who was wounded in the war in a way that leaves him unable to consummate the love he feels. He opens not with himself but with Robert Cohn, a wealthy, insecure friend whose romantic illusions Jake watches with a mix of pity and irritation. Around them moves a loose circle of expatriates who pass their nights in cafes and bars.
At the center is Lady Brett Ashley, a charming, hard-drinking Englishwoman whom Jake loves and cannot have. Brett loves him too, but her appetite for life keeps pulling her toward other men, including Cohn, with whom she has a brief affair, and her fiance Mike, who is broke and often drunk. The Paris chapters establish a world of wit, money trouble, and quiet pain underneath the surface chatter.
The group travels to Spain for the fiesta at Pamplona. Before the crowds arrive, Jake and his friend Bill Gorton take a fishing trip into the hills near Burguete. These pages are the book's calm center: cold streams, simple food, easy talk, and a release from the tangle of the others. It is the one stretch where the men seem at peace.
The fiesta brings everyone together and the tension breaks open. Brett becomes fascinated with Pedro Romero, a young and gifted bullfighter, and the jealousy among the men turns ugly. Cohn, unable to let go, beats several of them in his misery. Romero fights beautifully through it all, and Brett goes off with him before sending him away, telling herself she will not be one of those who ruins children.
In the quiet after, Jake collects himself alone, then answers Brett's call to come and help her in Madrid. The novel ends with the two of them in a taxi, Brett saying they could have had a fine life together and Jake answering that it is pretty to think so. Nothing is resolved. The sun rises and sets, the river runs to the sea, and the characters go on living inside a loss they have learned to carry but not to cure.