Elio and Oliver arrive in Rome by train and prepare in their hotel room for a night out at a book release party. The party is at a bookstore with friends and colleagues of Oliver’s. When they arrive, Elio meets a menagerie of guests who are all smoking, chatting loudly, leafing through books, and drinking scotch whiskey. He meets the author at the center of the celebration—the same one whom he met in B. and who inscribed copies for him and Marzia.
The book party is celebrating the release of Se l’Amore. The poet recites poetry and later recounts his experiences traveling in Thailand and living in Bangkok; in particular, he notes the sweet demeanor of all the people he met and his longing for Rome while he was abroad.
After much flirtatious banter with several of the partygoers, Elio and Oliver travel with the group to a restaurant for dinner, where the poet entertains them with a story about Thailand and a gender-ambiguous night clerk who attempted to woo him. The story deals with themes of love and desire, and the poet concludes with his idea of "San Clemente Syndrome," in reference to the Roman church built on top of multiple layers of catacombs from different communities and historical periods.
After dinner, the party goes for coffee and ends up at a bar drinking martinis, where an inebriated Elio entertains them on a piano. Feeling sick, he excuses himself from the bar. Oliver follows, and Elio vomits in a plaza. After washing his mouth in a fountain and feeling better, Oliver kisses Elio passionately against a wall. They end the night listening to drunken revelers on the street singing Neapolitan songs, translating them into English until daybreak. Neither realizes that this is the last night they will ever make love again.
The poet's story about the so-called "San-Clemente Syndrome" ends on an intentionally ambiguous note. It is up to the reader to decide exactly what the meaning behind his poetic concept is, though his anecdote and the mood and tone of this chapter point to clear themes of desire, erotic attraction, and festivity.
The Basilica of San Clemente is a three-tiered complex of buildings in the city of Rome. The present basilica is a Catholic church built in the Middle Ages just before the year 1100. Beneath this structure is a 4th century CE Christian basilica that had been converted out of the home of a Roman nobleman, part of which had served as an early church in the 1st century CE, and the basement of which had served as a temple to the Roman god of morning, Mithras, in the 2nd century CE. The home of the nobleman had been built on the foundations of a villa from the time of the Roman Republic, pre-1st century BCE, which had been destroyed in the Great Fire of 64 AD under Emperor Nero's reign.
The total structure includes Christian, Jewish, and Pagan catacombs. It serves as a symbol for Elio's experience of love and the more general human experience of desire: every new experience is built on a foundation of memories. The variety of religious traditions that inhabited the site of San Clemente, together with the poet's own story of a Thai gender-ambiguous night clerk, also contribute to Aciman's depiction of desire as an experience that is universally human, regardless of religious background, geographical point of origin, or gender preference.
The third chapter of the novel also marks the culmination of Elio and Oliver's relationship. After initial attraction, pining, desire, and frustration, the two finally resemble a committed couple; their romance is fully realized, even if only for three days. Mention of Oliver's impending departure from Italy is overlooked and understated; instead, the focus is on their love for one another. This results in a feeling of timelessness or suspension. Out of this experience in Rome, Elio receives his favorite memory with Oliver, when Oliver passionately and drunkenly kisses him against a wall and Elio puts his leg around him. This memory serves as a focalizing point for years to come, when he thinks about his relationship with Oliver and when he compares future romantic experiences. Elio notes, as he narrates this experience looking back, that neither he nor Oliver thought about the fact that this would be their last night together—contributing to the feeling of timelessness.