Max Brallier grew up in what any self-respecting horror geek would identify as “Romero Country”—the greater Pittsburgh area, cradle to director George A. Romero’s Night of the Living Dead, Dawn of the Dead and the birth of the modern zombie movie. It’s perhaps the most fitting of origin points for the author of The Last Kids on Earth series of children’s illustrated novels, even if Brallier was never really interested in horror films while growing up. Well, not until seeing Dawn of the Dead, anyway. Exposed to Romero’s biting satire on American consumerism, set amidst the zombie-aided collapse of society, Brallier began to imagine his own world of apocalyptic survival—except his protagonists haven’t yet made it to high school.

Four years after the publication of the first book in the series, Brallier’s stories have become best-sellers. The fifth entry, The Last Kids on Earth and the Midnight Blade, drops on Sept. 17, 2019—not coincidentally, the same day that Paste can exclusively announce Netflix will premiere the first animated special in the streaming giant’s Last Kids on Earth adaptation. The 66-minute special essentially serves as a feature-length pilot to the series, introducing its cast of “Last Kids” and establishing its setting, while adapting most of the material in Brallier’s first book. As in the books themselves, the primary challenge for Brallier as screenwriter was finding that deft balance between a genuinely scary setting and the desired tone of lighthearted comedy.

“It was always the thing that got pushback from my agents and publishers, the idea that you can’t really tell this fun story in this setting that should be overwhelmingly sad and gloomy,” said Brallier, who executive produces and co-wrote the adaptation with Scott Peterson. “That’s one of the things I was most worried about, trying to tell a fun adventure story where the kids are laughing and having a good time for the majority of it. I had to trust my gut, because a lot of people didn’t seem to get it at first. But I never got any pushback from the kids or teachers reading the book, which was key. We see this world through the lense of a hyper-enthusiastic, gung-ho, sort of relentlessly positive main character.”

That lead is 13-year-old Jack Sullivan, an orphan with few attachments to pre-apocalypse society. Voiced in the series by Nick Wolfhard, the older brother of fellow Netflix star Finn Wolfhard of Stranger Things, Jack is something of a stand-in for Brallier’s own childhood self, described by the author as being “the one person in this whole story who thinks his life is actually better in this world than it was before.”

“He’s relentlessly optimistic, to the point of being very cocky and sure of himself in some moments, but totally self-deprecating and frightened in others,” Brallier said. “Really, he wants to be this amazing hero because he’s very influenced by movies, comics and videogames. He wants to sit at the cool kids’ table, but he isn’t really the right person for that.”

Jack is joined by three of his peers to man a treehouse bastion against the legions of undead and the giant monsters who also roam their new world: Geeky best friend/technology savant Quint, reformed bully and monster-fighting expert Dirk, and impetuous star athlete June, who also happens to be Jack’s not-so-secret crush. They’re voiced by Garland Whitt, Charles Demers and Montse Hernandez, respectively, but the animated adaptation has also drawn considerable attention for the all-star lineup of vocal talent who will appear in its 10-episode second season, which is scheduled to follow the initial special in 2020. Those performers truly include the cream of the crop for voiceover artists, including Mark Hamill, Rosario Dawson, Catherine O’Hara, Keith David and Bruce Campbell. Brallier, understandably, is pretty excited to see his work come to life with such a top-flight vocal treatment.

The core cast of The Last Kids on Earth: Quint, Jack, Dirk and June.

“There was definitely a moment there, watching Mark Hamill read things I had written four years earlier in the book that was truly amazing,” he said. “I was just sitting there, squeezing my Coke Zero can in disbelief.”

As for who those performers are playing, Brallier and Netflix aren’t dropping all the details just yet. Campbell, he said, is playing a new character who didn’t appear in the books, but was instead created from the ground up to fit his personality. O’Hara, on the other hand, has been a prolific voiceover presence in films such as The Nightmare Before Christmas and beyond, and is playing “this interesting warrior monster, who has a lot more screentime in the show than in the books.”

In general, then, it feels like The Last Kids on Earth is building toward a considerably more expansive plot for its characters in the 10-episode second and third seasons, but Brallier and co. felt it was important to first establish the world of Jack, Quint, Dirk and June before bringing in such a slew of guest stars. The animated special premiering Sept. 17 represents a compromise: A way to do justice to Brallier’s first book and give backstory to all the core cast without spending an entire season just bringing the four kids together.

“The first book is ultimately very much about meeting the squad and assembling the team,” Brallier said. “They get to do one big battle, and we thought it would be really fun if it played like a movie. We needed to give that first story its time, because their world is going to get much more monster filled after this.”

Watching the animated special, it’s clear that a lot of runway is being established for where the story will head from here. There are obvious questions waiting to be asked about the cause of the sudden zombie invasion, what is happening in the wider world and the ultimate fates of several characters’ families. Brallier encourages these sorts of questions, while simultaneously not feeling too much of a need to dive into the minutiae of Jack’s post-apocalyptic daily existence, preferring to not get bogged down in details. When I needle him on how the kids are supplying their treehouse televisions with an unceasing flow of electricity, for instance, he just chuckles, knowing that the intended audience will be more focused on the characters than on such anal questions.

“They have a generator at the treehouse, okay?” he says. “It’s not Lord of the Flies over here. The primary focus is that this should be fun, and that’s how we’ve crafted the series. I can’t wait for people to see it.”

The Last Kids on Earth premieres Tuesday, Sept. 17, exclusively on Netflix.

Jim Vorel is a Paste staff writer and resident horror geek. You can follow him on Twitter for more film and TV writing.