Zombie movies are never just about zombies.

Classic zombie movies set in urban areas, from Dawnto Shaun, barely have to lift a rotting finger to say something about the mindless monotony of modern life; stories with a broader view, like 28 Days Laterand World War Z, are a bloody backdrop for political allegory. But no matter how macro the social commentary, they always come down to a handful of people massively outnumbered by a seething horde of single-minded monsters, and (usually) trying to help each other survive.

Little Monsters, a low-budget Australian indie horror-comedy starring Lupita Nyong’o, is no different in that respect — except that instead of a ragtag bunch of misfits, the humans at the centre of this zombie attack are three adults and a kindergarten class.

While the film initially focuses on Dave (Alexander England), a self-centred, guitar-toting manchild, the true main character is his five-year-old nephew’s ukelele-playing teacher, Miss Caroline (Nyong’o). Reeling from a nasty breakup and crashing on his sister’s couch, Dave is a rubbish uncle, constantly swearing in front of Felix and letting him play violent video games. After dropping Felix off at school, he instantly develops a crush on Miss Caroline and volunteers to chaperone a field trip to a farm to try and impress her. Unfortunately, the farm is right next door to a US military base, where some test subjects have broken loose. Dave and Miss Caroline quickly find themselves trying to shield the kids from both the flesh-eating undead and the truth of the situation — not to mention their favourite kids’ entertainer, Teddy McGiggles (Josh Gad), who’s actually a foul-mouthed alcoholic whose only concern is saving his own skin.

Going intoLittle Monsters, you might be expecting a fairly standard zom-com with an irreverent Antipodean twist and cute kids, like Shaun of the Deadmeets Black Sheeptinged with Kindergarten Cop. What you actually get is an emotional trojan horse, drawing you in with goofy gore and familiar genre beats before hitting you with a surprisingly affecting story about how being responsible for small humans is actually scarier than any monster.

“We're at a stage where we don't need to explain the rules of zombies anymore,” explains writer-director Abe Forsythe, whose previous films range from his gory-dumb teenage debut Nedto race-riot satire Down Under. “You just kind of show up, and they're there, and you get it, because we've seen it now 1000 times — but also for me they really represent the the horrors of the world and [forces] trying to corrupt our innocence.”

Being able to sketch out the horror elements in broad strokes means the emotional core of Forsythe’s script can breathe and shine, as Dave shakes off his selfishness thanks to his sweet, brave nephew (Diesel de Torraca, who is phenomenally believable), Taylor Swift, and the best fictional kindergarten teacher since Matilda’s Miss Honey.

Miss Caroline is sunny and patient, adored by the kids, and willing to do whatever is required to protect both their safety and their innocence — whether that means giving selfish grown men a discreet but terrifying talking-to (or a punch to the jaw), or taking out zombies with whatever farm implements are to hand, reassuring the kids that the gobs of viscera on her bright yellow sundress are just the remains of a “strawberry jam fight.” Nyong’o plays it straight, revealing the person underneath the teacher persona slowly, and proves to be, actually, very very funny. (She and Forsythe are working together again on another comedy next year.)

But while Miss Caroline radiates goodness, she’s still a real person, with a very human backstory that Nyong’o sells in a single, quiet scene. And the hard, constant work of fulfilling her duty of care to her class — including brightly keeping up the pretense that hiding from the zombie horde is a game, and nobody’s in real danger — is visible throughout the film.

That was crucial for Forsythe, whose original intention wasn’t to write a zombie movie, but a story about his own vulnerability as a single father sending his kid out into the world in the care of other adults, and a celebration of the teachers tasked with keeping other people’s children safe.

“[Miss Caroline] was a really important character for me,” says Forsythe, whose son Spike, now 8, has the same laundry list of potentially life-threatening allergies Felix has in the film. “It was about the year that my son went to school and I had to hand him over to someone else to basically protect him and protect his very specific health needs. I felt like I was taking on the responsibility of making a movie based around a teacher to celebrate teachers, but specifically kindergarten teachers.”

It was Forsythe’s script, with those realistic emotional stakes built on the bones of a genre film, that got the Hollywood stars on board.

“Lupita and Josh, they weren't telling their agents, 'Get me a low-budget zombie movie filmed in Australia,’” Forsythe jokes. “But what I wanted to say with this story, and these characters, lended itself to zombies being the best inciting incident to bring a whole bunch of stuff out that I could then explore with the themes of the story, and that's the stuff that got Lupita and Josh interested as well.”

Nyong’o actually filmed Little Monstersbefore her phenomenal double-duty turn in Jordan Peele’s Us, spending two weeks working with an Australian kindergarten teacher to help her grasp the specificities of professional kid-wrangling as well as the Australian school system. And when it came to meeting the eleven kids playing her class, she was introduced, Forsythe says, as Miss Caroline — “not as Lupita Nyong’o, the actress, from Star Wars”. (Frozenstar Gad, on the other hand, had no problems breaking out his Olaf voice for the young cast.)

A standout scene inLittle Monsterssees Felix’s allergies triggered, forcing Miss Caroline to venture out to retrieve an Epipen that’s on the other side of a lot of zombies. It’s not the kind of movie where the character herself is in any real danger — the enemy is time, as we cut from her fighting half a dozen zombies at once with a shovel, back to Felix struggling to breathe, as a stricken Dave and other kids look on helplessly. Forsythe, who’s been in similar situations with his own son, says that filming that scene was one of the most difficult things he’s done in his career — but having that contrast was crucial for Dave’s character development, and for the film as a whole.

“I don't get scared in horror movies if it's something that is fictional, something that is fantastical, unrealistic,” he explains. “And I think that's that's why I don't actually connect with horror movies generally, particularly a lot of zombie movies.

"But I learned in order to actually make the audience scared, you do have to make that based around something that is actually attached to reality, which is why that's the one segment in the movie where there is real danger — people can recognize [that scene] is coming from a very truthful place. So then adding Lupita having to run and get the Epipen and through the zombies… all of a sudden the zombies are standing in the way of something real.”

Little Monsters is streaming now on Hulu, in select Australian cinemas now, and out in the UK on Nov. 15,