On Monday, the narrator sees that the card on Holly's mailbox has been altered to include Mag Wildwood's name. He is interested in this development, but is then distracted by a letter in his own mailbox from a small university review. It informs him that the editors have agreed to publish his story in an upcoming issue. While the publication would not pay, the narrator is so excited that he forgets Holly's previous admonishment and knocks on her apartment door, eager to share the good news.
Holly comes to the door, clearly having been woken up. The narrator hands her the letter, and she takes a long time to read it. After offering her congratulations, Holly invites the narrator into her apartment and tells him she will take him out to lunch to celebrate. Waiting in Holly's bedroom, the narrator sees that it has the same "camping-out atmosphere" of the rest of the apartment, with no real furniture beyond the rather flashy bed.
Through the bathroom door, Holly tells the narrator about her decision to take Mag on as a roommate. While Mag isn't a lesbian, Holly explains, she is a "perfect fool" who had agreed to take on the lease and the burden of housework. Mag's modeling career means that she is out of the apartment most of the time. Moreover, Mag is engaged, which means that she and Holly will not be in direct competition for men. Holly explains that while Jose is a nice guy, there is a difference in height: "a foot, her favor".
Immaculately dressed and groomed, Holly treats the narrator to Manhattans at Joe Bell's bar. Hearing the good news of the narrator's story, Joe Bell offers them both champagne cocktails on the house. Holly and the narrator spend the rest of the day watching a parade on Fifth Avenue, eating lunch in the cafeteria park, and relaxing on the park's wooden boathouse porch. Holly asks about the narrator's childhood, and then relates the details of her own. The narrator notices that her own story, while pleasant, is "elusive, nameless, placeless, an impressionistic recital." He suspects that she isn't telling the truth, since he has heard that Holly had run away from home.
The narrator asks Holly if she had really run away from home at the young age of fourteen, and she admits that it is true; her previous story was a lie, made up because she didn't want to compete with the narrator's own tragic tale. Holly remembers that she wants to send her brother some peanut butter, and the two spend the afternoon haggling with grocers for jars of the wartime scarcity.
By the time Holly and the narrator have found six jars of peanut butter, it is dark, and the narrator takes Holly to the antique shop to point out the palatial bird cage he has been admiring. Holly admires it, but points out that "still, it's a cage." Spotting a Woolworth's, Holly drags him in, convincing him to steal something. The narrator feels watched, but, while the saleslady is occupied, he and Holly slip Halloween masks over their faces and exit the store without paying. He feels exhilarated, and the pair run a few blocks for dramatic effect. The narrator asks Holly if she had ever stolen before, and she admits that she used to, and still steals from time to time for practice. Happy, the two wear their stolen masks all the way home.
Section 5, which covers the narrator's conversation with Holly as they are preparing to celebrate the first publication of his writing, mainly serves to enhance the reader's understanding of Holly's resourceful and opportunistic nature. The narrator learns that, despite the seemingly friendly relationship between Holly and Mag, Holly has only taken Mag on as a roommate because she thinks her a "perfect fool" who would be willing to take on the lease and do Holly's share of laundry. As she does with the wealthy men in her life, Holly takes advantage of Mag, and expresses no remorse over her behavior. That the narrator considers Holly to be amoral is indicated by his assessment of her makeshift apartment, strewn with packed crates he compares to "the belongings of a criminal who feels the law not far behind."
The following section contains one of most memorable episodes in Breakfast At Tiffany's: Holly and the narrator's idle, adventurous day in New York City. The section deeply explores one of the novella's major themes: deception. Sharing an intimate conversation on Central Park's boathouse porch, the narrator and Holly exchange stories of their early childhoods. When Holly tells a vague, impressionistic story of a happy childhood filled with "swimming and summer, Christmas trees, pretty cousins and parties", the narrator realizes that she is lying. Holly admits the lie, but does not seem embarrassed or remorseful. Holly's constant fictionalizing of her own history and identity, as well as her willingness to lie to her friend, suggests her status as a "true phony": a person who lacks a true sense of self, and consequently, a sense of moral obligation to others. Also notable in this episode is the reader's lack of information about the narrator's childhood, which Holly relates was a "tragedy". The narrator tells his story to Holly, but it is not recorded in the narrative. The withholding of the narrator's story exemplifies the dynamic of the novella in which the narrator remains more remote from the reader than Holly, whose story he is telling.
Both the narrator and the reader's understanding of Holly as a "phony" is tempered, however, by her frequent mention of her brother Fred, with whom she imagines settling down with in Mexico. The details about Fred - he is tall, good with horses, and loves peanut butter - are among the few true details of Holly's life she discusses with others. Her attachment to and honesty about Fred suggests that Holly is not inherently deceptive; but rather her lies are ways to keep herself invulnerable in the face of the "mean reds": her shattering sense of not belonging to other people. Holly's efforts in this section to collect jars of peanut butter for Fred despite its scarcity casts a sympathetic light on Holly and implies that she might yet be redeemed.
The theme of deception in section 6 culminates with Holly and the narrator's theft of Halloween masks from the discount store Woolworth's. Holly admits to the narrator that she once stole out of necessity, but now steals only for the fun of the deception itself. Her nonchalant attitude towards theft again positions Holly outside the moral standards of conventional society. Holly's choice of masks - a classic symbol of deception and artifice - as objects of the theft they finalize her status as a "phony", a person who would rather perform a role than living an authentic life. As the narrator flees from Woolworth's in his stolen mask, he feels a sense of exhilaration as he steps into Holly's shoes, abandoning his careful personality to briefly experience life as she does.
Section 6 is also where the novella's motif of the birdcage is explored in depth. As the narrator and Holly wander through Central Park, they avoid the zoo, as Holly can't "bear to see anything in a cage." Later, when the narrator shows her the birdcage he admired in an antique store window, Holly points out that "still, it's a cage." Pathologically anxious about being restrained by relationships or even a stable lifestyle, convinced that she belongs to no one and nothing, Holly's fear of the cage represents her fear of being imprisoned by others. That Holly's dislike of cages is introduced in Section 6, which explores Holly's deceptive nature, is important. By aligning examples of deception with images of imprisonment, Capote suggests that Holly's "phoniness" is a defense against making herself vulnerable to others, and hence, to the "cage" of an authentic relationship.