‘Undertone’ review: A podcaster hears something haunting in immersive Canadian horror

Dir/scr: Ian Tuason. Canada. 2025. 94mins

This aurally atmospheric debut from Ian Tuason is more about things heard than seen, a genuinely chilling chamber piece which follows a strung-out podcast host’s descent into madness. Exceptional sound design and a superb central performance from The Handmaid’s tale star Nina Kiri, who is almost entirely alone on screen, mean the film casts a compelling spell, even when the narrative begins to succumb to genre cliché in its final reels.

Immersive, elemental horror

Premiering in Sundance’s Midnight strand ahead of a US theatrical release on March 13 via A24, Undertone should attract a keen audience thanks to effective marketing and strong word of mouth. It’s an impressive calling card for Tuason, whose virtual reality shorts have screened in Cannes’s NEXT Pavillion and racked up millions of views on YouTube. Indeed, he is emerging as a hot new horror talent, and will next be writing and directing the upcoming eighth film in the Paranormal Activity franchise.

That’s perhaps unsurprising, as here Tuason proves he can weaponise a supposedly safe space, turning a normal family into a foreboding, nightmarish place. That’s a well-worn trope, of course, harnessed by everything from The Exorcist to Poltergeist and recent canine horror Good Boy, but Tuason makes good use of his simple, single setting.

That’s the suburban Toronto childhood home of 20-something Evy (Kiri), who has reluctantly moved back to care for her dying mother (Michele Duquet). Exhausted and isolated, Evy also has the responsibility of helming popular paranormal podcast ’The Undertone’ with London-based co-host Justin (voiced by Adam DiMarco).

Their long-distance working relationship not only means that Evy is alone in the house, with only her comatose mother for company, but, because of the time difference, she must record over the phone with Justin in the middle of the night. So the set-up is already super creepy even before Justin plays Evy – who is supposedly the podcast’s logical voice of reason – a series of 10 voicemails he has received via anaonymous email. Recorded at an unknown time by couple Mike (voiced by Jeff Yung) and Jessa (Keana Lyn Bastidas), who were expecting their first child, the recordings depict an increasingly frightening series of events in which they are plagued by haunting nursery rhymes, insistent bangs and bizarre voices – which sometimes seem to emanate from Jessa.

Filming entirely in his own family home – in which he cared for his parents during the Covid Pandemic – Tuason makes the most of this intimate, self-contained location. Cinematographer Graham Beasley positions Evy at the edge of frame, lit only by the ghostly glow of her laptop, a dark expanse of hallway behind her. The camera often leaves her working alone at her desk to prowl the empty house. Off-kilter angles shift perspective, shadowy shapes swim in our peripheral vision. Lighting is either shadowy or sterile. Visually, it’s familiar, but it’s still undeniably effective.

Undertone really comes into its own via evocative, haunting sound design from David Gertsman, and a meticulously crafted 360-degree surround sound mix. When Evy puts on her noise-cancelling headphones, all ambient noise instantly disappears and we can only hear her conversations with Justin, the horrifying recordings, her ragged breathing. Occasionally another noise – a thud, a scratch, a voice – seems to filter in from elsewhere in the house, causing Evy to turn her head and, eventually, start to question what is real. As the recordings get more frantic, Evy’s scepticism turns to doubt and then abject fear, which begins to bleed into her interactions with her seemingly unresponsive mother.

Impressively shouldering what is essentially a one-hander – no-one else other than Duquet is ever seen on screen – Kiri gives a natural performance that keeps the supernatural elements largely in check. She mines well the character’s feelings of guilt and grief, as well as the oppressive impact of her mother’s devout faith – indicated in the Catholic iconography that clutters the home.

A personal discovery at the film’s mid-point raises the stakes for Evy and brings in some overwrought dramatic elements that overegg the narrative somewhat. Nevertheless, at its best Undertone works as an immersive, elemental horror, which successfully makes its audience question everything they hear.