A24's New Horror Film Is Already The Scariest Movie Of 2026 [Sundance 2026]

Fear is an intensely subjective thing, which means that something that's intended to scare will not always be successful all of the time. With that said, there's no question that the most powerful and reliable source of fear is our own minds. This is why many of the great horror filmmakers make use of various methods to try and get our own minds working for them and against us. 

Ultimately, most directors end up making the terrors within their movies tangible in some form. For instance, Ridley Scott does a diligent job of hiding and obfuscating the Xenomorph in "Alien," but the creature is ultimately still physically present in the film. That's why several movies that are generally thought of as the scariest of all time are ones in which the threat is largely kept off screen, the better to get audience's own fears to fill in the blanks. Two of these movies, "The Blair Witch Project" and "Paranormal Activity," have the added benefit of being presented in the found footage medium, creating something so grounded in realism that some audiences thought that what they were watching was real.

Director Ian Tuason's debut feature, "undertone," which A24 is releasing in theaters this March, takes a cue from these predecessors but goes in its own ingenious direction. While the film is still very much a visual experience, a large portion of it is exclusively aural. This approach helps make "undertone" not just the scariest film of this year's Sundance Film Festival, but also the scariest movie of 2026.

Similar to a great found footage horror movie, the way "undertone" uses sound to instill fear is baked right into the story of the film. Set (and shot) in Ian Tuason's native Canada, the film concerns Evy (Nina Kiri), a young woman who's put her life on hold after her mother (Michèle Duquet) fell mute and comatose, requiring Evy to become her sole caregiver. Evy also co-hosts a podcast called "The Undertone" along with her friend, Justin (Adam DiMarco). Justin lives in London, requiring Evy to record episodes with him at around 3 AM due to the time difference. The gimmick of "The Undertone" is that Justin is a believer in the supernatural while Evy is a skeptic, and each episode Justin brings forward a story or evidence of the beyond which Evy attempts to debunk.

On this particular occasion, Justin reveals that he was recently sent an anonymous email containing ten audio files. They appear to concern a young newlywed couple, Jessa (Keana Lyn Bastidas) and Mike (Jeff Yung), who began recording audio of themselves sleeping after being plagued by mysterious sounds during the night. Tuason and sound designer David Gertsman use this setup to deliver some extraordinarily creepy aural setpieces, in which we're seeing Evy listening alone in her home as we hear Jessa and Mike undergoing some harrowing experiences. One might wonder why Tuason didn't go ahead and make "undertone" an audio-only experience, creating fear from verisimilitude in the way found footage or something like 1992's "Ghostwatch" does. It turns out he has a very good reason, and this is seen in the way he composes long, lingering shots with lots of empty, dark space in them.

Ian Tuason has made a legitimately great horror film with "undertone," one which doesn't just deliver scares but also has an emotional depth to it that's genuinely upsetting. According to comments made by the producers at the film's Sundance premiere, Tuason was inspired to make the film due to his own experiences taking care of his ill parents during the COVID-19 pandemic — something which can be clearly seen in the movie itself. It's mixed together with Evy's own struggle as a natural skeptic who was raised by a deeply religious mother, a contradictory dynamic which recalls Dana Scully from "The X-Files." Nina Kiri is absolutely fantastic as Evy, giving a performance which looks effortless but is actually quite tricky. Given all the audio in the film and the various other actors who perform it, "undertone" doesn't feel like a single character movie, and yet it technically is. Kiri carries the film with aplomb.

"undertone" strikes at other, more universal sources of fear as well. There's some supernatural lore in the movie which is taken directly from real-life myth, and while I won't spoil which demon is namechecked, the fact that it has a basis in reality makes it eerie in the same fashion as William Friedkin's "The Exorcist." The film also makes heavy use of the concept of backmasking, where audio played in reverse reveals a secret message within the sound. "undertone" may not be analog horror per se, but these elements help make it that much more tangible and terrifying. Hopefully you're not too scared by all this to give "undertone" a look when it releases on March 13th, 2026.