‘undertone’ Review: A24’s Low-Budget Horror Rides the Podcast Boom

Independent, low-budget horror—often made by YouTubers or “content creators”—has become a phenomenon in recent years, fueled by projects that tend to be either formally inventive or highly viral. A little before the double impact of Obsession and Backrooms, Undertone opened in the U.S., a film that ticks several of those boxes: it carries the indie-cool imprimatur of A24, was shot cheaply in just a couple of locations, premiered at Sundance, performed solidly in theaters, and features a cast of largely unknown (and very few) actors. The rest? An initially compelling premise, a heavy reliance on sound over image, and a string of unsettling ideas the film puts forward from the outset.

undertone fits some of those trends but falls short on others. More specifically, once it establishes its intriguing, mysterious premise—pitched in a tone closer to drama than outright horror—it never quite figures out how to move beyond it. It tries, mostly by cranking up the volume and deploying a few familiar tricks, but the effort proves largely futile, and the film steadily loses momentum as it goes.

Director Ian Tuason sets up an unnerving central idea. Evy (Nina Kiri) hosts a horror podcast, The Undertone, alongside her friend Justin (Adam DiMarco), whom we hear but never see, as he broadcasts from another location. Justin plays the true believer, convinced that every story they feature either happened or could have happened. Evy is the skeptic, always ready with a rational explanation, reluctant to believe in almost anything. She also has a personal burden: her mother (Michèle Duquet) lives with her in a semi-comatose state, unable to speak or leave her bed. Still, when Evy least expects it, something around her mother seems to shift.

Most of the action, however, unfolds within the podcast itself—or rather, its production process. Justin wants to air a set of recordings sent in by listeners, as is often the case with the show. From the start, these tapes feel off. One features a couple discussing the dark undertones of children’s songs. Strange noises and what sound like invocations begin to seep into the audio. And while Evy clings to her skepticism, a series of events unfolding around her suggests that what they’re hearing might have far more sinister implications in the real world.

Much of the film is devoted to listening to and investigating these recordings. It’s an intriguing conceit at first, but it gradually becomes repetitive as both the messages and the situations they trigger grow less engaging. The process rarely changes: rewind the tapes to uncover hidden phrases, Google the references, then watch as those discoveries manifest—whether literally or through suggestion—in the protagonists’ reality. Religion, motherhood, and parent-child dynamics emerge as underlying themes in a film that ultimately stands out more for its sonic design—nearly all of its impact comes from what we hear—than for anything else.

Is that enough to turn it into a phenomenon? Probably not. But plenty of recent genre films break out—this one reportedly cost $500,000 and grossed $22 million—thanks more to social media momentum than to their intrinsic qualities. Still, despite its shortcomings, there’s no doubt Tuason is a filmmaker with talent. He’s already parlayed this into a bigger gig: directing the next installment in a mainstream horror franchise, Paranormal Activity 8, due in 2027. It may not be the dream assignment for a young auteur, but it pays the bills. There will be time, one assumes, to return to more personal horror filmmaking. Or maybe not. Perhaps undertone was simply his way in—and survival, for now, is enough.