Dealing with a dying parent can be one of life’s loneliest experiences. Doing that while alone an isolated house, with little company save for the recording of a supernatural podcast, is even more isolating. It’s a set of tensions that Undertone, A24’s latest horror outing, makes great use of. The setting makes ample use of this setting to deliver a thoroughly tense audio-centric horror. When you’re home late at night, sitting in the dark alone, you know how every single sound feels amplified and terrifying? Imagine that tension for an hour and a half. It’s an unusual but innovative approach to terror that excels largely because of spectacular sound design, careful narrative construction, and a strong performance from lead Nina Kiri. Altogether, Undertone is an immersive, haunting horror outing you can’t miss.

In Undertone, Nina Kiri plays Evy, a young woman caring for her dying (and effectively comatose) elderly mother (Michèle Duquet). It’s clear she loves her mother, and it’s also clear that the care (and never knowing if a breath will be her mother’s last) puts considerable stress on Evy, while subjecting her to isolation. Evy records a paranormal podcast with her friend and co-host Justin (Adam DiMarco), and in the time we spend with her, it’s her primary base of support and social interaction. When they receive a series of recordings from a married couple hearing noises at night, all’s fair and good (if mysterious) at first, but the deeper things get the more unsettling they become…, and it hits Evy at home.

Nina Kiri Carries Undertone With A Strong, Intense Performance

There aren’t altogether that many audio-focused films, and that’s partially because film is inherently a visual medium. There are plenty of great films before they even had sound (Keaton’s The General, Chaplin’s City Lights, Lang’s Metropolis, Murnau’s Nosferatu, just for starters), but ones that center on sound are few and far between. Fortunately, films like The Conversation, Blow Out, Pontypool, and Berbarian Sound Studio give Undertone a stellar series of forebears. The latter uses sound well, setting a character in extremely isolating conditions, and finds a successful route into its focus on the sounds (and her reactions). Undertone’s sound is immaculate and terrifying, building mystery into terror before it rises around the character, making for one hell of a successful auditory scare-fest.

Nina Kiri doesn’t have an easy task, given that her primary interactions within the film are, on the one hand, her comatose mother, and on the other, a voice on the other end of their recording session. With no interaction versus all-voice as the Scylla and Charybdis of Undertone, Kiri does a fantastic job carrying the film in isolation. She gives a stellar, believable performance full of subtlety and terror, amplifying the effectiveness of the audio design through her reactions. It’s exemplary. Shout out to Adam DiMarco as well, turning in a fantastic performance as the voice on the other end of the line. While Duquet spends a lot of the film bedridden and nonreactive, in the moments she’s allowed to be otherwise, her presence is strong.

Undertone is an Exemplary, Terrifying Auditory Scare-Fest

Nina Kiri looks behind her with worry while sitting at her desk in Undertone.

As a whole, Undertone is a strong exhibition of sustained tension. It sticks the landing, with an impactful finale that doesn’t let that tension down. Building up to the tension, it does lose some steam around the midpoint and into the third act. While it’s fantastic at squeezing fresh terror out of isolation and audio oddities, the tricks and slow build moments lose a little luster. Additionally, the minimalist approach to horror visuals largely works–it’s clear when things are happening, whether we see them fully or not–but it would be nice to see a little more. Nonetheless, it makes a lot out of a simple premiere, establishing a frightening process and a beautifully bleak finale.

Undertone is effectively an experiment. Isolating a character or set of characters (physically and emotionally) is common enough practice across horror’s diverse filmography, of course, but it’s rare to do so with Undertone‘s purpose in mind. The latter doesn’t just intend to jump scare you: it slows variables to a crawl in order to get inside your head, as it does Evy’s. It’s a spectacular exercise in control and tension, marking one of the most interesting horror films in recent years. Nina Kiri excels in carrying a film that almost completely rests on her shoulders, and the supporting players contribute well to the tension and emotional stakes.

At its core, however, the film’s a testament to stunning sound design. Sound designer David Gertsman and the film’s entire sound department cement a haunting hellscape, making Undertone a horror outing worth listening to. It’s scary as hell and one of the most unique horror films of our era. Watch it with the lights off and the sound cranked high.

Undertone hits theaters March 13, 2026.

For more Reviews, makes sure to check back to That Hashtag Show.

Keep Reading:

The Last Drive-In Series Finale Review