On July 20, 1714, an important bridge outside Lima, Peru, collapses without warning, plunging five travelers to their instant deaths. This unprecedented evet becomes a communal touchstone for the Limean population, which can’t fathom why such a catastrophe would occur. Especially interested is a friar named Brother Juniper, who witnesses the bridge collapse and afterwards becomes obsessed with proving that the disaster was a justified act of God. In order to do so, he investigates the lives of all the victims, recording even the most trivial facts in an enormous book, which he hopes will eventually help him understand why God allowed the bridge collapse to happen. However, “for all his diligence” Brother Juniper is never able to understand the “central passions” that motivated each of his subjects. The novel’s narrator muses that even though he believes himself better informed than Brother Juniper, he will also fall prey to the same problems.
One of the bridge collapse’s victims is Doña María, the Marquesa de Montemayor. Doña María is born shy and unattractive daughter of a rich Limean merchant; she frequently quarrels with her mother and eventually marries a poor nobleman solely in order to leave home. When she gives birth to a daughter, Clara, Doña María channels all her energy and insecurities into loving her daughter, but Clara grows up to be repulsed and hostile to her mother, and eventually marries a Spanish count in order to get away from her. Left behind in Lima, the Marquesa becomes increasingly eccentric, talking to herself in the street and often failing to dress herself correctly. In an attempt to gain her daughter’s love and admiration, Doña María writes her frequently; she turns out to be a gifted writer, and long after her death her dry and witty anecdotes eventually become an important and highly acclaimed record of her colonial milieu.
The only person who attends to Doña María is Pepita, a young girl who grew up in a Catholic orphanage nearby. She’s the protégé of the Abbess Madre María, a formidable woman who oversees most of the city’s charitable works. The Abbess wants Pepita, a kind and intelligent girl, to take over her work after her death, so she sends her to work for Doña María so that she can gain a better understanding of the world. Pepita doesn’t like working for the strange old woman, and she has no idea that the Abbess is preparing her for a more important job; however, since she’s a poor girl without any connections, she submits to her work without complaint.
Eventually, Clara informs her mother that she’s pregnant. This information sends the Marquesa into a frenzy of worry for her daughter’s health. She sends her numerous letters brimming with superstitious advice, and eventually decides to make a pilgrimage to a shrine outside the city. Bringing Pepita with her, she crosses over the famous bridge and meditates for a long time inside the church; at last, she’s filled with a new sense of tranquility as she realizes that she can do nothing to influence the course of her daughter’s pregnancy. As she and Pepita journey back to the city a day later, they both fall victim to the bridge’s collapse.
The novel proceeds to another victim, a young man named Esteban. As a baby, he and his twin brother, Manuel, are delivered to the Abbess’s orphanage and grow up under her firm but kind care. When they grow up, they work as scribes and errand runners throughout the city, remaining extremely close and living together; they even have their own language that they speak together. However, one day the brothers go to the theater, and Manuel instantly falls in love with the lead actress, Camila Perichole. He starts to lurk around the theater constantly and thinks of nothing but the Perichole; he’s thrilled when she summons him to see her one day, but she only wants him to transcribe her letters to her secret lover, the Viceroy of Lima. From then on, he frequently writes letters for her. Meanwhile, Manuel’s infatuation strains his relationship with Esteban, who feels betrayed that for the first time his brother has feelings that don’t include him. Eventually, Manuel realizes that he has to choose between his passion for the actress and his relationship with his brother. He choses to remain loyal to Esteban and brusquely informs the Perichole that he doesn’t want to write letters for her anymore.
Shortly after this, Manuel cuts himself on a piece of metal; the cut becomes infected, and despite Esteban’s devoted care, he dies after three painful days. Esteban’s grief almost drives him insane; he spends all his time roaming the city, and even the Abbess can’t calm or comfort him. Wracking her brain to think of a solution, she sends for Captain Alvarado. The Captain is a noted Peruvian explorer and friend to both the Abbess and Doña María; his restless journeying is a result of his grief for his own daughter, who died in childhood. Thinking that this man might comfort Esteban, the Abbess sends him to search for the young man. Captain Alvarado finds Esteban in Cuzco and asks him to join his crew for his next expedition. At first Esteban accepts the offer, but later in the evening he becomes upset and tries to hang himself; it’s only Captain Alvarado’s quick intervention that saves his life. The next day, they head towards Lima. When they reach the bridge outside the city, Esteban starts across before the captain and dies in the collapse.
The novel progresses to another narrative, that of Uncle Pio, Camila Perichole’s acting coach, assistant, and manservant. Born in Castile as the illegitimate son of a Spanish nobleman, Uncle Pio runs away to Madrid at a young age and works and scrapes out a living through his inventiveness, charisma, and cunning. Although he’s good at every job he undertakes, he can’t bear to stay settled in one for long. His one passion is Spanish literature and theater, which he comes to know by working in and around the Madrid theaters. After a particularly bad scrape in Madrid’s underworld, Uncle Pio flees to Peru, where he discovers Camila Perichole, an abused young girl singing in seedy cafes. Seeing her talent, Uncle Pio takes her home and teaches her to sing and act, eventually touring her around the whole continent as a performer. He’s generally kind to the girl, but pushes her hard in order to make her perform well.
Eventually, Uncle Pio and the Perichole return to Lima, where she becomes the star of the city theater. Her success makes her somewhat complacent and less interested in her work. She becomes the mistress of Don Andrés, the Viceroy of Peru and learns to desire conventional respectability, rather than success as an artist. Eventually, she stops acting at all, begins to attend church, and moves to a fashionable neighborhood in the hills outside Lima. With the Viceroy, she has three children; her favorite is the beautiful and sensitive Jaime. Perichole distances herself from Uncle Pio, who she sees as representing her lowly origins.
One day, the Perichole contracts smallpox and loses her famous beauty. Devastated, the actress secludes herself in her house, gives away all her jewels and fine clothes, and permits no visitors. In this time of crisis, Uncle Pio takes over the management of her house and children, even lending her money. The Perichole becomes angry with him and kicks him out of the house, but eventually he convinces her to let Jaime live with him in Lima, instead of being trapped in the gloomy house with no company. Reluctantly, the Perichole concedes. The next day Uncle Pio packs up all Jaime’s things and they set off for Lima. Crossing the famous bridge into the city, they become the bridge collapse’s last victims.
After the bridge collapse, Brother Juniper is convinced that “the world’s time had come for proof” that all events, even the most catastrophic, are the result of God’s will. He’s already tried to prove this principle before—when a plague struck his parish, he attempted to rate all the villagers based on piety to see if there was any apparent logic in the deaths. However, he couldn’t find any patterns. Now, Brother Juniper embarks on an exhaustive investigation of the bridge collapse, but this endeavor is also confusing: “he thought he saw in the same accident the wicked visited by destruction and the good called early to Heaven.” Eventually, the Spanish Inquisition decides that Brother Juniper’s book is heretical, and he is burned at the stake in Lima.
Some time after Brother Juniper’s death, the Archbishop of Lima holds a memorial service for all the victims. The Abbess attends, full of mourning for Pepita and Manuel; moreover, she has to face the fact that without her protégé, it’s unlikely that anyone will continue her work after her death. The Perichole also attends the service, leaving her house for the first time since her illness. Afterwards, she seeks out the Abbess and asks the older woman for spiritual advice. The Abbess listens to the actress tell of her son and her grief, and she shows her around her abbey’s gardens. While the two women are talking, Doña Clara arrives, also seeking guidance from the Abbess. The Abbess comforts both women by showing the abbey and all the ways in which it helps the city’s poor and orphaned. Both women are inspired by the Abbess’s energy and goodwill.
After the visitors leave, the Abbess stands in the dark garden and reflects that soon not only Esteban and Pepita but everyone who knew them will be dead as well—not even their memory will remain. However, she’s comforted that her belief that “even memory is not necessary for love” and that love provides an enduring connection between the living and the dead.