Netflix’s Apocalyptic Hit Is Leaving Viewers Baffled. The Book Has Clues.

This article contains spoilers for Leave the World Behind.

The No. 1 movie on Netflix this week is Leave the World Behind, writer-director Sam Esmail’s adaptation of the excellent novel of the same name. Why is it such a hit? Perhaps it’s because the film stars big names Julia Roberts, Ethan Hawke, and Mahershala Ali. Perhaps it’s because the film amps up the much more subtly stated disaster-movie elements of the book, adding set pieces like an oil tanker running aground on a beach and appealing to apocalypse junkies still unsatisfied by all six series based on The Walking Dead. Or perhaps it’s because the novel that the film is based on is by Rumaan Alam, who viewers might miss from his previous work as a Slate advice columnist.

Even though the movie is a lot more explicit than the book, with Netflix levels of exposure have come some befuddled responses, which you can find on sites like Letterboxd, where some viewers are singling out the ambiguous ending. “So? What now?” writes one. “Alright so what was the point??” writes another. The Letterboxd people can join the Goodreads fans, who have been writing different flavors of “Huh?” in their reviews of Alam’s novel for years.

Confused film viewers may be interested to know that the end of the novel, like the movie, tells you very little that is definitive about the disaster and about what will happen to the characters in the future, but Alam does employ a few strategies of oblique suggestion that fill in some blanks. One of those is foreshadowing. Roberts and Hawke play the Brooklyn couple Amanda and Clay Sandford, who go on a last-minute getaway with their teen son and daughter to a house on Long Island—a vacation that’s interrupted when G.H. Scott (Ali), the owner of the house, shows up in the middle of the night with his daughter, Ruth (Myha’la), bearing bad news about what’s going on out in the world. Both novel and film depict the teenage son, Archie (Charlie Evans), horrifyingly losing his teeth at the beginning of the third act, perhaps in response to a series of sonic blasts. But the book is clear about Archie’s fate. In a sickening and memorable passage, Alam writes that Archie, after his teeth fall out, pokes his tongue into the “tender empty pockets” left on his gums. “They were soft and pleasant, like the recesses of the human body his own was designed to fit into, something he’d never know firsthand,” Alam writes. “Could he forgive the universe that denial of his own particular purpose? He wouldn’t get the chance.” Sorry, Book Archie! Archie in the film may or may not survive, depending on your level of optimism.

The ending of the movie already has a fair amount of body horror to offer, but the book has far more. Archie’s sickness—what it might be, how many might have it—hangs more grimly over the novel’s ending than the film’s. Clay is at one point described as not noticing “the tingle in his knees, his elbows, or he did and took it for fear.” What’s that tingle? It can’t be good! In another flash forward, we hear that the wife in the Thorne family, the absent people who own a house that the teen daughter, Rose, explores at the end of both novel and film, is stranded at an airport in San Diego, and sometimes dreamed of her house on Long Island “before she succumbed to cancer in one of the tent camps the army managed to erect outside the airport”—a quick timeline that implies her cancer may have also come from the mysterious noises that seem to have affected Archie. And we hear that Karen, the wife of Danny, the contractor to whom G.H. appeals for help with Archie’s situation, is about to lose her teeth, as well.

The Danny of the novel is far less of a prepper than Kevin Bacon’s angry conspiracy theorist of the film, a caricature who serves to amplify the film’s themes of discord between people. Book Danny is certainly not friendly, and wants G.H. and Clay to leave his property, but he’s not violent toward them, and he doesn’t know much about what’s gone on, either. “Had to be a plane. I don’t think there’s any information getting out, so I assume it’s a war … Has to be an attack I think?” he says. “They were talking about the super hurricane on CNN. The Iranians or whoever—they planned it right. The perfect shitshow.”

Alam’s novel doles out information about the global shitshow sparingly. Instead, we get glimpses of people around the world reacting to, and becoming victims of, whatever has happened: a man trapped in an MTA elevator, babies dying in the NICU, restaurants grilling the contents of walk-in refrigerators and handing them out for free, a mother drowning her daughters in the bathtub. It’s a collage of individual stories, meant to suggest something large—a life-changing event—that we perceive only in flashes.

The movie, on the other hand, has G.H. deliver a speech to Clay about how he fears a scenario described by a defense industry client of his—an enemy-imposed progressive destabilization of American life, achieved via cyberattack, information blackout, and citizens turning against one another in civil war. This is just G.H.’s theory of what has happened and will happen, but the movie gives it some credence via the confrontation between Danny and G.H. and Clay, and then by showing the skyline of New York City as we hear gunfire and watch mushroom clouds rising over it.

In the novel, Rose, the Sanfords’ daughter, is a point of light—she’s described as “a survivor.” Book Rose does put Friends in the DVD player—not the series finale, but “the episode where Ross fantasized about Princess Leia”—while she is at the Thornes’, but it’s just as background noise. Far from the movie’s anxious, tablet-addicted teen, the novel’s practical Rose is already adapting to the situation better than the rest of the people in her group. She’s a character familiar from prepper fiction: the emergent pragmatist, who will do well in the new world. She scopes out the house to find out what they have—“Band-Aids, Advil, a package of batteries”—and to see whether this place would be a good place for her family and the Scotts to stay. There’s no extremely modern bunker like the one Rose finds in the movie, with its vague promise of long-term salvation. There’s just Rose, moving on with life. Alam, for his part, doesn’t seem to have minded this change to this character. In an interview with Variety, he called the movie’s Friends-in-the-bunker ending a “jolt of humor,” describing it as “so satisfying and so rewarding.”

The dissatisfaction with the endings of the book and the movie comes from the confusion of genre that comes with widespread distribution of a more challenging text. People may be reading the book looking for a thriller, or watching the movie expecting another The Day After Tomorrow or 2012, and not enjoying the ambiguity they find. The movie is “something that is possessed by its audience,” Alam said to Variety, and that “respects the viewer” enough not to provide closure: not to show the families together in the bunker at the end. Viewers might expect an escape from reality, something as comforting, in the end, as a Long Island getaway, or another episode of Friends, but Leave the World Behind doesn’t give it to us. Still, I think they get there. Do you?