The following version of this story was used to create the guide: Díaz, Junot. "Monstro".The New Yorker, June 4, 2012. Pages 107-118.

The unnamed narrator looks back from an unspecified time in the future to when he was 19, in answer to the question of what he was doing when the world came to an end. It was the hottest March on record when the first case of the bizarre infection known in the Dominican Republic as “La Negrura,” the “Blackness,” showed up on the arm of one little Haitian boy living in a relocation camp on the outskirts of the Haitian capital Port-au-Prince. The boy’s arm had become overgrown with a pustulant black mass, and doctors were baffled at what they were seeing. Soon, there were thousands of cases, but this disease did not follow the known patterns of transmission and seemed to spread without direct contact. Because of the excessive regional temperatures brought on by global warming accelerated by deforestation, the strange outbreak was initially blamed on the heat. And because the outbreak was happening in Haiti, concentrated among the sickest and most vulnerable living in the camps for people already displaced by natural disaster, it was mostly ignored by the world for several months as it multiplied.

The narrator explains that just before the apocalyptic events described in the story, he was living with his mother in Brooklyn when she becomes sick with a hemorrhagic virus. In order to take advantage of the lower medical costs and the support of her extended family, the narrator’s mother rents out the house where they had been living and goes to stay in Santo Domingo while the narrator finishes his year at Brown University. Unable to find a summer job or an internship due to the lingering results of drought and economic collapse, the narrator decides to spend the summer with his Dominican family and keep his mother company.

He runs into Alex, whom he knows from Brown as one of the few other Dominican students there, and although they had not been close friends before, they soon begin hanging out regularly. Unlike the narrator, who is dark-skinned, working-class, and throughly Americanized without much connection to the Dominican Republic, Alex represents the nation’s patrician class of old money Hispanic elite whose extravagant, decadent lifestyle provides the narrator refuge from the monotony of unfamiliar island life. The narrator does not care for Alex’s snobby, similarly privileged friends, but he is instantly smitten by Mysty, an affected, spoiled law student and former model with a Francophilic distaste for her home country.

Meanwhile, doctors in the Haitian quarantine area have been observing that infected patients from all over the area have been drawing together, some of whom travel hundreds of miles to congregate in the middle of the quarantine zone outside the largest relocation camp in Port-au-Prince. A doctor tries some experiments in trying to remove various infected patients to secure, remote areas on land and at sea. In all cases, the patients, regardless of age, either unshackled themselves from whatever restraints had been holding them back or died trying, in order to free themselves to return to the central quarantine zone, as if drawn by a homing beacon.

Back in Port-au-Prince, a Haitian doctor named De Graff encounters a camp sanitation worker brought in by his wife after weeks of unexplainable behavior that she attributes to witchcraft. Although the man shows no sign of infection with La Negrura, he has been having amnesiac states of agitation, displaying the same irresistible urge to commune with the diseased in the quarantine zone as those infected. Someone acquires a sensitive thermal scanner which is pointed at the patients with symptoms like De Graff’s patients whose bodies all emit blue pulses of electromagnetic energy. After scanning themselves to reveal a normal baseline of red energy emission, the team points the device out the window to the streets of Port-au-Prince and is horrified to see that one in eight people scanned blue. Rushing to the hospital in the quarantine zone, the scientists discover that every single aid worker and staff member scans blue. The zone is locked down, and a team from the World Health Organization (WHO) is airlifted in, only to be slaughtered by the mob of infected who then release a communal shriek lasting nearly half an hour.

The narrator designates this as the moment when chaotic violence consumes the relocation camps in the quarantine zone as men, women, children and the elderly take up any available weapons to embark on a murderous rampage against each other and anyone else in their path. Some video images from the carnage are broadcast, causing the authorities to quarantine the whole country of Haiti and seal the border with the Dominican Republic against hundreds of thousands of Haitian fleeing the violence. After two weeks of inactivity, the U.S. government sends in a force of ground troops, who are similarly routed by the bloodthirsty infected.

According to leaked classified documents and confirmed by witnesses on the ground, after this failed siege an American bomber plane loaded with powerful incendiary weapons is secretly dispatched over Dominican airspace. Dr. De Graff, who has survived the ongoing massacres, is heading away from her birth city of Port-au-Prince when the bombing begins. Before the white thermal flash that can be seen around the world and blinds her in one eye, De Graff sees for herself what had become of the infected. The narrator mentions rumors about the scene in the camps just before the so-called Detonation Event, which the narrator never believed until he sees for himself, referencing two Polaroid photos depicting a 40-foot-tall human-devouring giant now known as a Class 2.

When the bomb drops, the narrator is at a nightclub in Santo Domingo, where he and Mysty are dancing with intoxicated passion. The narrator experiences supreme happiness at that moment, when Mysty unexpectedly allows him to lean in and kiss her in earnest before suddenly changing her mind and pulling away, leading to an exchange of insults just before the lights go out. Seismic monitors in distant locations register a massive shockwave after the detonations that releases a magnetic pulse that deaden all the electrical activity within 600 miles. The pilots who dropped the bombs crash into the sea, as a dozen passenger jets fell out of the sky unable to navigate or communicate, with ships sinking at sea and civil infrastructure failing. Alex wants only to grab his Polaroid camera and head to the Haitian border to document the unimaginable horrors reported by the millions of new refugees. Like fools, Mysty and the narrator follow him.