The basement is quiet. Not the good kind of quiet, the kind that settles in when the house has emptied and the world outside has agreed, for now, to leave you alone. This quiet is different. It has texture. The laptop glows against a young woman’s face, casting the room in pale blue while everything behind her dissolves into darkness. She pulls her headphones on, leans into the screen, and presses play. From somewhere in the audio file, deep in the grain of the recording, something stirs. A sound that should not be there. She rewinds, listens again and the sound is closer now. She leans in further. Behind her, in the dark she can no longer see, the room has changed.
And soon…so will she.
That is the world of Undertone, the haunting new horror film from A24 that opens in theaters March 13, 2026. From the very first frame, it makes one thing abundantly clear: the most terrifying place in the world is not a haunted house, a dark forest, or an abandoned hospital. It is the space between what you hear and what you imagine.
The Film That Reinvents Found Horror
Writer-director Ian Tuason has been building to Undertone for his entire career. A veteran of 360-degree immersive virtual reality horror shorts, his YouTube work accumulated over 14 million organic views and screened at SXSW, the Fantasia International Film Festival, and the Marche du Film NEXT Pavilion in Cannes. Before that, his 2015 short 3:00am racked up 9 million views after being shared by Ashton Kutcher and Lil Wayne. All of it was preparation for this moment.
The premise of Undertone is deceptively simple. Evy Babic (Nina Kiri) is the host of a popular paranormal podcast. She is also, at the moment the film begins, caring for her comatose mother in her childhood home, running her show from the basement in the dead of night while her mother slowly dies upstairs. A series of audio files arrives anonymously, apparently recording a pregnant couple being terrorized inside their own home by something invisible and malevolent. Evy and her remote co-host Justin (Adam DiMarco) begin analyzing the recordings. Furthermore, as they inch closer to what the files contain, whatever is inside them begins to follow Evy back out.
That structural conceit, the horror that migrates from the recording into the listener’s world, is the engine of everything Tuason has built here. Consequently, Undertone does not rely on jump scares or CGI spectacle. Instead, it relies on something far more primal: your own imagination, filling in the spaces the film deliberately leaves dark.
“Sometimes the most terrifying thing of all is our imagination, and what we project onto something that may or may not be there.” Ian Tuason, Writer-Director
A Director Who Understands Sound as a Weapon
Most horror films treat sound design as a support system for the visuals. Tuason treats it as the primary instrument of terror, which is what sets Undertone apart from almost everything else in the genre right now.
Having spent years pioneering immersive 3D audio for live-action VR content, Tuason brought that expertise directly into the architecture of this film. Rather than designing sound in post-production as an afterthought, he wrote audio directions into the shooting script itself. A baby cries behind you. A body tumbles down the stairs from right to left. Something that was far away is, without warning, directly behind you. The 360-degree soundscape was built to function like a second camera, one that points in directions the lens cannot follow.
Central to the film’s unease is audio apophenia: the psychological phenomenon of hearing hidden messages in audio that has been reversed or distorted. Tuason’s podcasters spend the film parsing nursery rhymes played backward, listening for signals in the noise, and finding patterns that may or may not be real. The horror of Undertone is, above all, the horror of interpretation. You, the viewer, are constructing the monster in your own mind, using only what the audio gives you. As a result, the film is different for every person who watches it, because every imagination is different, and every imagination is capable of something uniquely terrible.
The sound was completed in Dolby Atmos, expanding the 360-degree aural experience into a full surround-sound assault. Notably, Tuason recommends watching the film in a theater. After one listen, you will understand why he feels strongly about that.
Nina Kiri Carries the Weight of Two Worlds
A film this interior, this dependent on a single sustained performance, succeeds or fails entirely on the strength of its lead. In Undertone, that lead is Nina Kiri, and the film succeeds completely.
Best known internationally for her 29-episode run as Alma in Hulu’s The Handmaid’s Tale, Kiri brings to Evy Babic a quality that is rarer than it sounds: the ability to make denial feel like a survival strategy. Evy is a recovering alcoholic, a grieving daughter, and a woman who has organized her entire psychology around the belief that the supernatural is not real. Over the course of 94 minutes, each of those defenses is dismantled, one by one, with the careful precision of someone who knows exactly which wall to remove last.
What makes the performance remarkable is that Kiri never plays the horror externally. Rather than reacting to what she sees, she reacts to what she hears, and that distinction is everything. The headphones create a closed world inside a closed world, isolating Evy from the room she sits in and from the mother dying upstairs and, gradually, from her own certainty about what is real. We descend into that isolation alongside her, step by careful step, until we are as lost as she is.
“I don’t think there’s anything more terrifying than taking care of a dying parent. That’s real terror. When it hits Evy at the same time all these horrific outward elements surface, she has to come to terms with the situation she’s in.” Nina Kiri
The House as Character, Heaven as Hell
Tuason shot Undertone in his own childhood home in Rexdale, a suburb of Toronto, the same house where he nursed both his parents through terminal illness during the COVID pandemic. That biographical layer is not incidental to the film. It is the film’s foundation, the reason every object in every frame feels chosen rather than placed.
Production designer Mercedes Coyle transformed the modest two-story home into a space of suffocating psychological geography. Upstairs belongs to Mama: cold, sterile, lit like a hospital ward, populated with Catholic iconography and the quiet surveillance of religious portraiture. Downstairs belongs to Evy: warmer, more rational, the realm of the podcast and the living. As Evy’s grip on reality loosens, those two worlds begin to bleed into each other, and the geography of the house becomes the geography of her unraveling.
Moreover, the staircase between them is the film’s moral axis. Going up means confronting death and whatever has taken up residence alongside it. Coming back down means returning to sanity, to the podcast, to the voice of Justin on the other end of the line. At a certain point in Undertone, Evy stops coming back down the same way she went up. That is when the film becomes something genuinely unforgettable.
Composer Shanika Lewis-Waddell, the Canadian experimental pop producer known under the name shn shn, provides a score that breathes rather than announces, meditative and unsettling in equal measure, built from lush vocals, swelling pads, and a stillness that feels, counterintuitively, like a held breath.
The Origin Story That Makes the Film Matter More
Understanding where Undertone came from deepens what it means in ways that are difficult to overstate.
In 2020, as Tuason was developing his script, COVID shuttered Toronto’s medical infrastructure. Both his parents received terminal cancer diagnoses simultaneously. Unable to access hospital care, Tuason moved back into his childhood home to become their caregiver. His mother died within months. His father followed two and a half years later. Alone in that basement, writing the film while grieving the people dying above him, Tuason built Undertone out of the rawest material available: his own haunting.
The character of Evy Babic is, by Tuason’s own account, him. The caregiving guilt, the crisis of faith, the way that grief blurs the boundary between what is real and what your terror has conjured from the dark. All of it is honest. None of it is managed at a safe distance. When his father passed, Tuason used the modest inheritance from the family home to finance the film himself, shooting it with a skeleton crew in early 2025 in the rooms where it all happened.
Undertone was subsequently sold to A24 in July 2025 in what press noted as the largest sale of a Canadian film in history. Before that sale, it had already won the Audience Award at the 29th Fantasia International Film Festival and earned a coveted slot in the Midnight program at the 2026 Sundance Film Festival. In both cases, the response from audiences was the same: shaken, sleepless, and unwilling to put their headphones on for the walk home.
“Evy was me. Everything that ended up on the screen, or in the speakers of Evy’s headphones, was intentional and honest, and meticulously thought out.” Ian Tuason
Should You See Undertone?
Yes. In a theater. In the dark. With the best sound system available.
Undertone is the kind of horror film that the genre produces once in a long while: one that earns its terror through architecture rather than spectacle, through patience rather than shock, and through an understanding of human psychology that goes deeper than most horror is willing to reach. It is, at its core, a film about grief, about the borderline between belief and denial, and about what happens when you can no longer be certain which side of that line you stand on.
Ultimately, the most unsettling thing about Undertone is not what Evy hears in the audio files. It is that you will hear it too. And long after the film ends, in the quiet moments before sleep, you will find yourself wondering whether the sound in the recording was always there, or whether you put it there yourself.
That, in the end, is the film’s most devastating trick. The horror was never in the recording. It was in you. Undertone simply knew how to find it.
undertone | Directed by Ian Tuason | Starring Nina Kiri, Adam DiMarco, Michèle Duquet, Keana Lyn Bastidas, Jeff Yung | Not Yet Rated | 94 minutes | A24 | In theaters March 13, 2026.
Learn more at a24films.com
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