Returning by subway from a job interview, the narrator sees a passenger reading a newspaper with the headline "Trawler Marries Fourth". He assumes that Trawler's bride is Holly, and is surprised. He explains that he hasn't seen Holly since the Sunday following Doc's visit, having been depressed after losing his job and learning that he may be drafted into the war effort.
Thinking about Holly and Rusty, the narrator is disappointed. He realizes that he is a little in love with Holly, in the way that he was once in love with his family cook and a neighborhood postman as a child. His love for her is no less potent for being unromantic or asexual. "That category of love generates jealousy, too," he explains.
At the next subway station, the narrator buys a newspaper and discovers to his relief that Rusty has not married Holly, but Mag Wildwood. When he returns to the brownstone, he finds Sapphia Spanella raving in the hallway, begging him to call the police. From behind Holly's door, the narrator hears the sound of crashing glass and furniture being overturned. He is soon joined by Jose, who brings a doctor. Jose opens the door with his own key. Inside, the three men find the apartment wrecked, all the contents smashed, and Holly lying on the bed in a stupor. The doctor injects Holly with a sedative while she rants incoherently about her brother, Fred.
While the doctor attends to Holly, the narrator and Jose discuss her outburst. Jose confesses that, given his high political office, he can't afford a public scandal. The narrator assumes that Holly's tantrum was provoked by Rusty's marriage to Mag, and Jose corrects him by passing him a telegram from Doc Golightly in Texas, which informs Holly that her brother Fred was killed in action.
The narrator relates that Holly never mentioned her brother again and stopped calling him Fred. Over the summer, Holly becomes a recluse, letting her hair darken and putting on weight. Jose moves into the apartment, though he is often in Washington. Nevertheless, the narrator explains, Holly seems happier, content learning to keep house, furnish her apartment, and speak Portuguese. She cooks elaborate, unsuccessful meals for Jose and the narrator, and begins talking about her future as Jose's wife. Holly confesses to the narrator that she is six weeks pregnant.
Elaborating on her devotion to Jose, Holly tells the narrator that though she has only had eleven lovers, she is happy to be leaving her promiscuous lifestyle behind. She tells him that she is tired of pretending to love men that she knew were "rats", and that excluding Doc, Jose was her "first non-rat romance." While Jose is not Holly's ideal man, she loves him, and caring for him gives her a sense of satisfaction.
Through the final weeks of summer, the narrator and Holly become closer, learning to communicate in silence. When Jose is out of town, he and Holly take walks to Chinatown and watch ships from the Brooklyn Bridge. Holly tells him that, one day in the future, she will return to New York on one of those ships, "me and my nine Brazilian brats." She confesses that she loves New York, even though the city doesn't belong to her and she doesn't belong to it. The narrator explains that he felt suddenly left out as Holly continued on her lifelong travels.
Section 10 marks the first point in their friendship where the narrator realizes he is in love with Holly. Jealous of what he assumes is Holly's marriage to Rusty Trawler, the narrator begins to explore his feelings about her. He compares his love for her to the affection he felt for his family cook, his neighborhood mailman, and "a whole family named McKendrick." He suggests that this love was nonetheless powerful because it was non sexual, therein touching on another of the novella's main themes: the diversity and validity of loving relationships among adults. Moreover, in clarifying the asexual nature of his feelings for Holly, the narrator again implies that he is a homosexual.
Upon hearing of her brother's death, Holly's behavior is violent and self-destructive. She smashes glass and upturns all her furniture in a fit of despair, not caring who hears and without regard for the consequences. While Holly had described her bouts of the "mean reds", her behavior throughout the novella is remarkably upbeat and nonchalant, illustrating her minimal personal investment in her relationships. However, her rage at Fred's death indicates that her attachment to her brother was quite real and strong. The extremity of Holly's despair further suggests why she avoids permanent relationships, as her experience of pain is apparently intense and self-destructive. Avoiding real attachments is perhaps Holly's way to protect herself against the kind of pain she feels at her brother's death.
Fred appears to symbolize Holly's sense of freedom; a recurrent fantasy of hers was that the two of them would escape to Mexico, where they would raise horses. Accordingly, at Fred's death, Holly allows Jose to move in, thus "caging" her in her own apartment. She transforms herself into an "un-Holly-like" version of a stable, domestic housewife. She furnishes her apartment - something she claimed she wouldn't do until she felt she "belonged" - and stops dying her signature multi-colored hair. She becomes pregnant and attempts to learn cooking and Portuguese. She repeats to the narrator that she is happy and that she loves Jose, claims that appear too emphatic to be entirely sincere.
In an extended monologue, Holly justifies her reasons for settling down, claiming that she was tired of her promiscuous lifestyle, "rat" boyfriends, and her bouts of the "mean reds". Section 11 thus documents another of Holly's transformations. Yet, while Holly seems happy, the narrator is unconvinced that she has indeed settled down. He notes that while she is proud of her cooking, it is actually awful. The disjunction here between Holly's thoughts and reality indicates that, unlike her role as a socialite, "domestic wife" is a fictional part that Holly plays badly.
While section 11 ostensibly deals with Holly's transformation, it is implicitly concerned with the narrator's particular character flaw: his reluctance to be anything but a passive observer of his own life. While he recognizes that he loves Holly, he does not tell her this, and rather allows her to settle into a relationship with Jose that could take her to Brazil forever. The narrator's passivity is, in fact, exaggerated in this section by the fact that he has no dialogue apart from his telling Holly "do shut up." This remark is provoked by a sudden anger at his feeling "left out - a tugboat in dry dock while she, glittery voyager of secure destination, steamed down the harbor." The narrator recognizes his perpetual feeling of exclusion is, like a boat moored to a dock, holding him back. However, he does not take direct action to change this quality.
The final metaphor of the section, which compares the narrator's final days with Holly to autumn leaves blowing in the wind, indicates the banality of Holly's new personality. Like leaves, the narrator can't tell the days apart, as they are all alike. The reference to autumn leaves, which are on the verge of death, symbolizes the end of the narrator's friendship with Holly.