Undertone (2025) Review – A Personal, Sound-Heavy Horror with Mixed Results

Welcome to Knockout Horror. Today we are taking a look at recent A24 Canadian supernatural horror movie Undertone (2025). Undertone has been doing the rounds in cinema screens for a while but I would expect it to hit streaming very shortly. This has Shudder written all over it. Little piece of advice: wait for your favourite streaming service to pick it up. I’ll explain why as we go.

Before we start, I apologise for the lack of content recently. I managed to come down with the flu which absolutely sucked but I’m getting back on my feet now.

The Scariest Movie You’ll Ever Hear?

That’s a bold claim: “the scariest movie you’ll ever hear“… It’s plastered all over advertisements, it was in the trailer, and it has become the number one hook with Undertone’s marketing. It’s clearly a line designed to go viral. This is a classic example of a production company keying the viewer in on a movie’s gimmick before they have even sat down with their popcorn.

“Undertone is exactly that but for Gen Z; some will buy into the hype hook, line, and sinker, while others will be woefully disappointed.”

For someone who grew up in, and became a horror fan during, the 90s, it is very reminiscent of other movies that relied heavily on their marketing. The Blair Witch Project and Paranormal Activity jump to mind immediately. They are both films where the marketing suggested you pack an extra pair of pants only to basically set you up for disappointment.

Undertone is exactly that but for Gen Z. Some people are going to buy into the hype hook, line, and sinker, others will be woefully disappointed. The plot is very simple; Evy (Nina Kiri), the host of a spooky-stuff podcast, moves in with her terminally ill mother to become her primary caregiver. After she and her co-host are sent a series of strange audio recordings taken by a couple, Evy begins to see the content of the recordings bleed over into her own life and home.

The best way to think of this movie is as something of a chamber piece like The Apology or even Pontypool. The entire events take place in one small home, the cast is minimal, there is a heavy focus on conversation and unsettling sounds, and there’s an almost “made for radio” quality about the production. To be honest, it feels quite unique in its restraint and that’s where Undertone’s strength lies.

Spooky in its simplicity

The bulk of the exposition comes from ten separate conversations featuring our troubled couple, received by Evy’s co-host Justin (Adam DiMarco). These range from the mundane “you talk in your sleep so I am recording you” to the much more sinister.

Expect a certain degree of escalation as one recording bleeds into the next but it’s not until Evy begins experiencing strange events in her own home that the movie becomes a full blown horror. This is where things turn up a notch and the film sheds its drama heavy skin.

There’s nothing in the way of special effects and CGI demons here. Undertone’s scares come purely from what you can hear. This is one of those movies that wants you to grab a set of sound cancelling headphones or a decent surround sound system and crank it up a little.

“It feels quite unique in its restraint and that is where Undertone’s strength lies.”

When Undertone is at its best, it is keeping things simple. The story is allowed to fade into the background so the viewer can indulge in some of those admittedly effective recordings and watch the background a little for sinister looking shadows. There’s no need for plot deep dives; just focus on what works and keep giving us a reason to listen closely.

It’s very trope heavy

I feel like things start to slip up a little when Tuason attempts to dial up the frights. In doing so, he leans heavily into tried and tested methods that we have all seen before a million times. With this in mind, how scary you find Undertone depends heavily on your own tolerance for played out horror tropes.

If deep demonic voices and nursery rhymes played backwards terrify the pants off of you then you will have a great time. If not, well, you may just be a little disappointed.

For the most part, the tropes are well executed and delivered with enough panache to keep viewers who enjoy this type of thing on edge throughout but it’s just so familiar. I spent a lot of my viewing time trying not to roll my eyes. I suppose there is always the plot to fall back on.

Writer and director Ian Tuason based much of this movie’s story on his own experiences caring for terminally ill parents in 2020. He also set the movie in his own childhood home.

With that in mind, some of Undertone’s focus on the emotionally crippling predicament Evy finds herself in (an experience I, myself, have been through) helps some of the horror and themes land a little harder. There’s just enough story to give you something to bite into and just enough plot building to bring everything together pretty neatly.

So why was I disappointed?

I watched the trailer for Undertone in the cinema and immediately felt it would be one of those movies I would either love or simply feel apathetic to. For me, watching it proved to be the latter.

“The scares have all been done before; when you break away those pieces, there is very little to grab onto.”

Whilst I think it is going to massively hit home for lots of viewers and terrify the pants off of younger fans, I just didn’t find it all that scary or compelling. It’s extremely trope heavy and, due to that, very predictable. Horror vets will probably feel like they have seen it all before.

It reminded me slightly of Good Boy in as much as it was another movie reinventing the horror wheel through the medium of gimmicks. The sound heavy approach does work well but it’s nothing new and the scares have all been done before. When you break away those pieces, there is very little to grab onto.

I couldn’t help mentally comparing it to the 2022 movie Monolith, as well. It’s very similar in approach and that only serves to dilute some of Undertone’s originality.

On the plus side, though, this is a decent looking movie. Tuason shows some flair when it comes to shot choices and the whole picture has a deep moodiness that serves to drag you into Evy’s world pretty damn effectively.

Speaking of Evy, Nina Kiri does a very nice job in the lead role. I can’t say the same about DiMarco, as Justin. He appears only in voice form but he’s very wooden. Some of that might be down to some clumsy screenplay work. There’s an occasional AI quality to it and the script can feel padded and a bit awkward.

All in all, Undertone is a movie that would serve as a fantastic sleepover movie but it just didn’t resonate with me the way I hoped it would.

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Horror is a genre that thrives thanks to indie film makers and low budget creators. At Knockout Horror, we firmly believe that every movie that we review deserves a fair fight. That's why we grade on a curve. Our star ratings are all about context, judging a film on what it achieves with the resources it has.

A 4-star rating for a scrappy indie horror made for $10,000 is a testament to its ingenuity and raw power. A 4-star rating for a $100 million blockbuster means it delivered on its epic promises. We don't compare them side-by-side; we celebrate success in every weight class, from the back-alley brawler to the heavyweight champion. Please keep this in mind when considering star ratings.