You really only need a few key elements to make a very effective horror movie, and for writer/director Ian Tuason, those are location, performance and sound. He builds his directorial debut, “Undertone,” out of a creepy house, an incredible actor (Nina Kiri), and a command of cinematic sound that doesn’t just provide the atmosphere, but the story itself.

This is a one-woman show for Kiri, who plays Evy, a young woman stuck in her childhood home while caring for her dying mother (Michèle Duquet). Tuason crafts the oppressiveness of the space both visually (her religious mother has crucifixes everywhere) and sonically (the ticking clock, mama’s ragged breathing, the vibrating notifications from her boyfriend’s insistent phone calls).

Evy’s only escape is into her noise-canceling headphones; her only lifeline a call from her longtime friend Justin (Adam DiMarco). In the wee hours of the night, Evy and Justin record a spooky podcast “The Undertone,” where Evy plays the skeptic, Justin the “Santa believer,” the pair debating and debunking real-life horror stories and urban legends. One night, Justin brings a series of mysterious recordings he’s received from an anonymous emailer to the podcast, recordings that become so disturbing that Evy struggles to maintain her composure and her character as the in-house cynic.

In cinema, sound is the invisible net that holds all the visual elements together. If the sound in a film is wonky, the entire endeavor will read as false or inauthentic; if it’s excellent and even overpronounced, sound can terrify you down to your bones. In channeling his creative resources toward the sound of “Undertone,” Tuason conjures a lot out of a simple concept — a girl in a house. The marriage of this sound design to thoughtful, carefully placed camera movements makes for a horror film that’s a suspenseful slow burn.

Tuason and cinematographer Graham Beasley establish the camera as suspicious, lurking in hallways and foyers, studying Evy from afar. They effectively weaponize the pan, as every time the camera moves, unmotivated, we dread what it might reveal. Tuason avoids cheap jump scares, even playfully teasing at them, but when nothing is revealed, we keep searching the frame, in vain, again and again. Maybe this time it’ll reveal what’s hiding in the shadows.

Justin’s audio clips start out as simple nighttime recordings to capture a woman named Jessa (Keana Lyn Bastidas) talking in her sleep, but turn into something much scarier, seeming to capture a demonic possession and a baby in danger. They burrow into Evy’s consciousness, as night after night, she tries to research her way out of this spook, while her day-to-day life crumbles around her (her dying mother, her deadbeat boyfriend, her drinking problem). Eventually, her own reality cracks, the recordings acting like an infectious haunting, technologically transmitted, and “Undertone” reveals an edge of genuine danger, like a sonic version of “The Ring.”

Evy’s story and the tale that unwinds on the tapes is one of mothers and children: the guilt that Evy feels as a daughter watching her mother die, wondering if she’ll ever be good enough to be a mother herself. Her mother lies in bed, nearly catatonic, but she becomes an active part of the horror of “Undertone” too, as Evy’s psyche splinters while grappling with a tale of maternal possession and children in danger unfolding on the tapes.

Tuason doesn’t dive deep into these themes and what they mean for the characters however, it’s more that he presents a series of related concepts that serve as a thematic framework for his exercise in crafting and maintaining cinematic suspense and tone.

With these ideas swirling, Tuason conducts “Undertone” to a fever pitch, a maelstrom of sound and fury that is spookily effective, if frustratingly nonspecific. It’s almost as if he doesn’t know how to end things, but oddly enough, that ambiguity only adds to the strange unknowingness of the piece, in the same way that the mysterious recordings and spooky tales motivate Evy and Justin’s podcast. Without any clear answers, we’re left only to piece things together ourselves, and whatever we can imagine is only scarier than what Tuason could have spelled out.

———

'UNDERTONE'

3 stars (out of 4)

MPA rating: R (for language)

Running time: 1:33

How to watch: In theaters March 13

———

©2026 Tribune Content Agency, LLC