At last month’s Denver Film Festival, some of the queasiness of Cam, a stylish thriller from Boulder natives Isa Mazzei and Daniel Goldhaber, leaked off the screen and into the theater.

The Kafkaesque thriller might best be described as identity horror. Loosely based on Mazzei’s experience in the world of live-streamed performance known as “camming,” the film follows a sex worker whose likeness is stolen and exploited, dashing her once-anonymous online identity against her quiet suburban life.

So, when a man in the festival audience laughed at Mazzei as she introduced herself as a former sex worker, it was disquieting.

“That was the first time I realized ‘Oh, people are not going to be OK with this,’” says Mazzei, 27, sitting around a kitchen table across from Goldhaber, 26, on a quiet morning in North Boulder. “When I was camming, there was such a line between my private and public life. Now, that’s gone. It’s scary.”

Making Cam was a crucible for Mazzei and Goldhaber. Mazzei, its writer, mined a deeply personal slice of her life for the screenplay; Goldhaber scrutinized his default views on sex work and gender while gearing up to direct it. The duo hired a couple’s counselor to help them resolve the conflicts that bubbled up between them in the three years it took to make the film (but no, they’re not together).

“We put everything we had into this in a way—financially, emotionally, health-wise,” Mazzei says.

That effort has paid off. Since hitting Netflix last month, Cam has become a cult hit. Even horror maestro Stephen King tweeted praise of the film, which sits at an impressive 93 percent on review aggregate site Rotten Tomatoes. (Mazzei is already writing another unnamed female-driven genre film through Blumhouse Productions, which Goldhaber is lined up to direct.)

Former high school sweethearts, the pair talks in tandem, unspooling each other’s thoughts mid-sentence, sometimes nudging one another down one conversational hamlet and then blocking another.

“We wanted the audience to be inside a sex worker’s head,” Mazzei says. “To feel what that was like.”

“With a documentary, it’s always about looking into this other world,” Goldhaber adds.

“You’re inherently outside the world looking in,” Mazzei says.

The film is the capstone on a feverish creative partnership the duo first struck up in high school when Mazzei joined Goldhaber’s theater troupe. He became her creative confidant; Goldhaber is who she’d turn to for notes on her novel, the first substantial thing she’d written.

“He said, ‘I don’t think you’ll ever be a writer,’ “ Mazzei says, shooting Goldhaber playful daggers. “Which is very ironic, given the nature of things now.”

After they broke up and graduated, Mazzei started camming, eventually asking Goldhaber to shoot her first pornographic film. Until then, Goldhaber, who studied film at Harvard, hadn’t considered porn as filmmaking.

“All of the sudden, I started thinking about all the pornographic media I was consuming as being crafted,” he says. “That was a cool idea. I wanted to engage with that further.”

From there, they started in on the project that would become Cam. It was initially conceived as a documentary on Mazzei’s time as a cam girl. But as the duo thought of how to best align an audience with its sex worker protagonist, they settled on making it a narrative genre film.

Mazzei and Goldhaber took strides to make Cam’s production as thoughtful as the film itself. On set, they vigilantly fought against male-gaze camera angles, the practice of icing women’s nipples, and other sexist filmmaking tropes that were glaringly problematic.

Crucially, they held the mirror to themselves, too. On Mazzei’s request, Goldhaber went as far as to try camming out for himself in the week leading up to the shoot.

“I remember afterward, he said, ‘Everyone just kept trying to make me do stuff for free,’“ Mazzei recalls. “I was like, ‘Welcome to being a sex worker! Welcome to being a woman!’ I thought it was really important he be able to feel that to the extent it was possible.”

“The idea was to understand a teeny little sliver of the vulnerability of having your body naked online,” Goldhaber says. “We think of those things in documentary filmmaking but we don’t think about the ethics of representation in narrative enough.”

As the film’s director, Goldhaber said the experience was simply “the call of duty.” That attitude likely explains Cam’s resonance, as Goldhaber recounts a key piece of wisdom from his Harvard thesis advisor, French filmmaker Philippe Grandrieux.

“He said to me, ‘If a movie is to be transformative for the audience, it must have been equally as transformative for the filmmakers to create,’” Goldhaber says. “Seeing that quote on its own, maybe that sounds pretentious as shit. But that’s the hope. And that is, fundamentally, my and Isa’s ethic.”