Sundance ‘26: ‘UNDERTONE’ is Actually the Scariest Movie in Years

Anytime a new horror movie comes out, horror fans and critics trip over themselves to call it the scariest movie since Hereditary, which was the scariest movie since Paranormal Activity, which was the scariest since The Blair Witch Project, which was the scariest since The Exorcist, and so on in an endless horror ouroboros of escalating hype. Well, Undertone, a possession movie about paranormal podcast hosts who stumble upon a ten-part series of increasingly cursed audio clips, is actually, hyperbole aside, the scariest movie in quite some time. It earns that title not with jump scares or gore, but with an impressively economical command of its audience’s every sense. Writer-director Ian Tucson sets his hooks early, relying on restraint, minimalism, and some of the best sound design in the genre to ratchet tension from subtle unease to full-body chill.

Evy (Nina Kiri), the skeptical half of the popular paranormal podcast The Undertone, finds comfort in the rational. Case after case, she remains the intellectually minded pragmatist. Everything has a logical explanation. Which is why her mother’s slow death feels so impossible to intellectualize. She tells her London-based cohost Justin (Adam DiMarco, channeling strong Aaron Mahnke-from-Lore energy, and only heard, never seen) that their weekly recordings are the only thing keeping her sane. Her life at home, caring for her dying mother, is defined by a grim kind of structure. She’s isolated and alone, entombed in the childhood home that once held love, prayer, and children’s songs. That same house becomes the film’s only location. What was once a nest becomes a tomb. And those children’s songs are twisted and corrupted, laced with hidden messages and demonic incantations, echoing through the walls.

As Evy and Justin record their newest episode, responding in mic’d up real time to the mysterious audio files sent to them, they get to know the voices on the tape: Mike and Jessa, a married couple expecting a child. When Jessa starts talking in her sleep, Mike starts recording. What begins as harmless somniloquy turns sinister quickly. As the podcast hosts go deeper into the recordings, they unearth a folklore buried inside innocuous-sounding children’s songs. Played in reverse, they contain sinister commands and eerie warnings. Something ancient. Wicked. Threaded through time.

And through all of this, we really only spend time with Evy. Aside from her comatose mother upstairs, she’s the only onscreen character. She never even leaves the house. Even the one time she does, the film cuts around it. We never see the outdoors. That decision intensifies the claustrophobia. The walls are closing in, and the camera never lets you forget it. It’s frankly incredible what they’re able to pull off with so little. A single location, mostly a single room, only two onscreen characters, and a mythos carried almost entirely by sound design.

The sound design is everything here. It is immersive, layered with found audio and intimate headset listening. You feel it in your spine. It is overwhelming in the best way and also does the heavy lifting of propelling the plot forward. It is not just window dressing. It is the story. It is integrated beautifully and stands out even in a genre that often thrives in this territory.

Kiri is an absolute find, delivering a nervy performance that blends horror and grief with total control. She is electrifying even in stillness. As the only face onscreen for most of the runtime, she often isn’t doing much, just listening and reacting, but she becomes the axis around which the whole film spins. She brings a sort of calibrated stillness when needed, cooling the room so the heat has somewhere to go once things begin to boil. When she finally starts to believe in what she’s hearing, it lands with real weight.

The direction is immaculate. It plays with negative space and shadows and uses genre tropes just enough to nod at them without ever slipping into smugness. It is meta without being self-congratulatory. This is the kind of horror that earns a few nervous laughs as release valves but remains relentlessly suspenseful and, at times, genuinely terrifying. I honestly cannot remember the last time I got this many chills in a theater, Undertone operating on the same scare frequency as Hereditary or the original Conjuring. All atmosphere, dread, and the slow unfurling of something ancient and awful. Watch this with the best sound system you can find and prepare to be thoroughly terrified.

CONCLUSION: A masterfully assembled nightmare of all-encompassing horror, Ian Tucson’s ‘Undertone‘ is as immersive as it is bone chilling, featuring truly elite sound design.