In the text, Malorie arrives at her destination, a school for the blind, and encounters a community of people who have blinded themselves so they could never be victims again. The Netflix adaptation has a milder, sweeter ending. She also finds a school for the blind, but it's a joyful place, a haven filled with chirping birds that can warn of monsters' presence and children playing. There, she finally gives Boy and Girl names.
"I think there are plenty of horror directors who are like, 'No, we've got to end on the idea that humanity is screwed and we're all doomed because that's life,'" says Heisserer. But he advocated for the change from the beginning, noting that the decision to end the movie in a different way than the novel came, in part, from the idea of who might be immune to the effects of this enemy before the apocalyptic event. "It seemed smarter for us to make that more of an optimistic ending. I'm one who generally leans toward a hopeful or optimistic ending even in dystopian horror movies. I'm not one to embrace nihilism considering that I feel like we're living in that world now."
Heisserer read the novel before it was published in 2014 and worked on drafts of the screenplay for about four years before leaving the project around the time Bier came on board. It director Andy Muschietti was initially attached. (As for those A Quiet Place comparisons, Heisserer argues its possible that that film was actually inspired by Malerman's work.)
Though the supernatural villains remain non-corporeal throughout the entirety of the film, representing by gushes of wind, he and Malerman had discussions about their physicality. "For many drafts, the creatures did have a weight and a certain shape or form," he says. "But what they looked like we never really went into detail. We did need to know some other information about it so we could figure out, 'Well, can it enter into a house or another building? How much does it weigh? What does it bump into?' That was helpful for a lot of the set pieces."