The story opens with David waiting in his apartment on the day Giovanni is scheduled to be executed. He reflects on how he discovered his own homosexuality and the various ways he tried to resist, including his relationship with Hella. His resistance broke down, at least partially, when he met Giovanni however, but his shame prevented him from falling fully in love.

David's mother died when he was very young—about five years old—and so he is raised mainly by his father and his aunt, Ellen. From very early on, his father seems either incapable or unwilling to truly be a father and wants to, instead, just be David's friend. David is never satisfied with this relationship but realizes after a serious automobile accident that he and has father will never have the kind of intimacy that he wants. When he is a young boy—probably about thirteen or fourteen—he has his a sexual encounter with Joey, his best friend. He is so ashamed by it—and so worried that he will lose his masculinity—that he completely cuts Joey out of his life and hardly speaks to him. He keeps his sexuality a dark secret, a secret which becomes a great burden to him.

When he arrives in Europe he meets Hella, an American girl who also happens to be traveling through Europe. The two start dating and it becomes serious enough that David asks her to marry him, though he is not at all sure that he truly loves her. She decides to take some time away, in Spain, to think about it. Meanwhile, David meets Giovanni, the barman at a Paris gay bar. Jacques, who is openly gay, is attracted to Giovanni, but the latter shows no interest in him. David and Giovanni, however, hit it off immediately and talk at length. David is very unsure of himself and what he wants to do, but Giovanni is very aggressive with his attraction. The two wind up having sex that night.

David is almost completely out of money and so decides to live with Giovanni. The months they spend together almost seem like they occur in some other dimension, out of time. David is unquestionably happy with Giovanni but is not willing to completely open up with him. He is still held back by the shame over his sexuality. He receives a letter from Hella telling him that she has decided to return to Paris and has accepted his marriage proposal. He is terribly conflicted and does not know whether he wants to stay with Giovanni or have a "normal" life with Hella. In order to prove to himself that he is still attracted to women, he has a casual sexual encounter with an acquaintance named Sue, but the encounter does nothing to encourage him; indeed, his lack of interest in Sue only makes him think a relationship with Hella will be hopeless in the long term.

When he returns to Giovanni's room, Giovanni is in a frenzy. His boss at the bar, Guillaume, fired him and he suspects that it was out of jealousy over his relationship with David. Giovanni wound up getting so angry that he punched Guillaume and was thrown out. The two now face a truly dismal financial situation, for neither has a job and they have only a little money between them. David says he will write his father and get some money, but puts it off; he wants to decide what he is going to do with Hella first. Hella finally returns and David sneaks out of the room and spends several days with her without talking to or seeing Giovanni. Their first few days together are happy, but David quickly begins to suspect that his feelings for her do not run very deeply. They run into Jacques and Giovanni at a bookstore. Giovanni, evidently, has been devastated by David's disappearance. They plan to go out for drinks together, but David stands them up and instead stays with Hella. He goes to Giovanni's room the next day—ostensibly to retrieve some of his belongings—and has a last, heated argument with him. Giovanni says that David was too scared to really embrace their relationship and, as a result, never really opened himself up to Giovanni. David insists that it is absurd to think there could be anything between them because they are both men. This argument has little effect on Giovanni, though, and he points out that David should know what they could have based on what they have already had. Though David knows he loves Giovanni—more than he could ever love Hella—he refuses to cave in and leaves.

David returns to Hella and they make plans to leave Paris, perhaps for somewhere in the south of France. They then hear the news that Guillaume, Giovanni's boss, has been murdered and Giovanni is the primary suspect. While traveling France, David keeps apprised of Giovanni's situation through the newspapers and what their mutual friend, Jacques, tells him. He is caught about a week after the murder and is eventually sentenced to death. David is unmistakably distraught by Giovanni's fortune and winds up spending several days having sex with a sailor and his friends. Hella discovers him and finally understands why David has been so distant. She leaves him as soon as she can to return to America. David stays in France until the day of Giovanni's execution.