“I have two almost 4-year-olds, and I’m quite powerful and influential in certain circles, but not with two 4-year-olds,” says Joel Edgerton. “Kids run their own country, in a way.”

Edgerton’s been thinking a lot lately about those nascent years before entering adulthood thanks to his latest project, The Plague, which looks at the complicated and occasionally terrifying social dynamics of kids — specifically adolescent boys.

The feature debut of director Charlie Polinger, the film is set in the world of a competitive water polo summer camp, focusing primarily on the dynamic within a group of 12- and 13-year-old boys who have ostracized one camper because he has “the plague,” a nasty-looking case of eczema. One camper, Ben (Everett Blunck), struggles between his desire to help the outcast camper and his worry about incurring the wrath of the larger group. In the film, Edgerton plays the well-meaning if ineffective water polo coach.

“In the age of renewed questions about and considerations of the manosphere, The Plague is a prescient title,” wrote THR critic Lovia Gyarkye in her review of the film, which is quickly becoming one of the stand-outs of the fest.

Beyond displaying considerable range as an actor in everything from Baz Luhrmann’s The Great Gatsby to Paul Schrader’s The Master Gardener and George Clooney’s The Boys in the Boat, Edgerton is also a filmmaker — he received a DGA nom for first-time director for his 2015 thriller The Gift, which he also wrote and starred in.

Ahead of Cannes 2025, where The Plague is set to screen in the Un Certain Regard section, Edgerton talked to THR about the inherent horror of being a preteen: “I’ve often said about school experience that it’s like a documentary where you’re watching a depleting watering hole in the African savanna.”

What drew you to a story that is focused on a gaggle of 13-year-olds?

I’m really interested in this idea of when do we become responsible adults. There is an untethered, unchecked period of our life, even though we have parents, we have teachers and, in this case, camp counselors. There’s a nature in children that is natural, that can be beautiful or can be dark. It’s through a passage of experiential moments that we learn what makes others around us feel good, and therefore how that reflects our own character and that shapes who we are. I thought the journey within this film of the central character was a really, really interesting universal exploration of how we shape ourselves in the world. I just wanted to help make sure that the movie got made.

What was it about the script that had you saying, “I want to help it get made”?

There’s a real careful attention and accuracy to how children — while they might be terrible at understanding the ramifications or the collateral damage that they can cause — are excellent at socio-diplomacy. They learn where to position themselves within a flock or a herd. They understand hierarchy. They understand what is dangerous and what is safe. Whether we believe those instincts and cues to be good ones, they very quickly discern where they need to stand and with whom. Ben’s journey is about understanding that it’s dangerous to be caring towards the ostracized, wounded member of the group, but his nature draws him in that direction and draws him into the danger as well.

There is the old adage in film about not working with kids and animals, but in this movie, you are only working with kids. How did you find the experience?

I always marvel at kids, whatever the ages of kids that I’ve worked with. You’ll work with a child who’s never been in a film before and you’ll learn something from them. Kayo [Martin], who plays the bully, he could run rings around me to the point where we would shoot things, and when the lines were blurred, I wanted to throttle him. He knew that his job was just to be cocky to everybody, and so he didn’t stop with me. I don’t just look upwards to the older, wiser actors. There’s something to be learned from everybody. It’s very impressive, too, on Charlie’s side, to create the sense of danger for the character of Ben. Intention and effect are different things. I might say something just to make my friends laugh at me that really hurts you. I think there is a real accuracy and detail within that for the film. It’s not just like bullies going, “I’m going to be mean.” It’s “I’m being mean because I’m trying to survive.” For Kayo’s character, his way of surviving is to be the leader of a group.

When you put it like that, being a kid is pretty Darwinian.

The adult world has its own governing set of rules, and we impose those on our own children, supposedly to show them the ropes to the world that they’re about to take a hold of. But children have their own language, their own rules. They create them. They create their own society. Then an adult, like my character, becomes a foreigner within their country.

You are really the only adult in the film. What did you see as your character’s position in the middle of the kids’ dynamic?

Adults can hover around a camp or a school or a household, but they can’t be all knowing and all seeing. Their advice or their own experience can reflect or offer wisdom, but it doesn’t necessarily help when you’re living in the pain of something. Ben may remember my character as Charlie remembers his experience 30 years later, but I can guarantee it’s hard to receive all of that parental wisdom or teacherly wisdom when you’re in the midst of the turmoil of living in a nation of children. This was the closest thing I’d ever read to a Lord of the Flies type scenario — a society built and run and organized by children. I’ve been a big fan of movies like Thirteen in the past, because they’re like a peephole or a window into a life we don’t get to experience once we’re of a certain age. We don’t know how kids talk when they’re with each other. I think we’re all scared of them. I think we’re scared of youth.

There are times where the movie feels like a true horror film, like there is something audiences should be truly afraid of onscreen.

I’ve often said about the school experience that it’s like a documentary where you’re watching a depleting watering hole in the African savanna, crocodiles, and there’s a baby antelope and everything in between. It’s a dangerous place, and anything can happen. There’s something really Full Metal Jacket about this movie. There are similar tones to this.

I thought the choice of setting it inside a water polo camp was interesting. What did you think of having it set in that world specifically?

It could have been anything. It could be a tennis camp, gymnastics or whatever the culture. The specificity of that culture, cinematically, is beautiful, and the confines of being in one swim center and the danger of the water is very potent. Through the experience, I was just thinking back to so many experiences of my own as a child and everyone on the crew was talking about that stuff. Childhood is full of sentimental, beautiful memories, but it’s also full of crazy trauma. Those things diminish over time, we move on, and events get swallowed up, but they’ve all made their little kind of scars.