Undertone

Towards the end of this fleetingly freaky one-location horror about a young podcaster who claps on her headphones, clicks on a sound file and invites evil into her life, the screen goes black and the audio takes over. It’s an unusual and effective moment: horrifying surround-sound screams and screechings go beetling through your brain and your imagination does the rest. If there were such a thing as an aural cleanse, you’d need one when the credits roll. 

If only the rest of Filipino-Canadian filmmaker Ian Tuason’s podcast horror lived up to that trapdoor-drop moment. Weaponising the cinema’s Dolby Atmos into a delivery mechanism for frights is a clever ploy that Undertone never maximises.

Evy (The Handmaid's Tale’s Nina Kiri) is the host of a horror podcast in the mold of True Scary Story or The Dark Paranormal. Because he’s in a different time zone, and also because things are way more unnerving in the dead of night, she slips downstairs at her mother’s home each night to record with her co-host Justin (an unseen Adam DiMarco of The White Lotus). Upstairs in the beige house, her rasping, barely conscious mum is dying. The vibes are, to put it mildly, bad. 

Evy’s full name is Evangeline. Like the crucifixes on the walls, it’s a clue about the suffocatingly devout upbringing she’s been subjected to. On the podcast she plays the part of wary skeptic, egged on by Justin to embrace whatever weirdness lands in their inbox in the name of content. So when 10 audio files arrive from a random email address, what else is there to do but click.

If there were such a thing as an aural cleanse, you’d need one when the credits roll

Stepping stones into the darkness, those audio clips give the film its structure as Justin and Evy try to piece together the disturbing story of a young couple who have unlocked a demonic presence. Can this evil spread through the audio itself? Hey, why not stick on the headphones and find out? 

Tuason channels his grief for the loss of his own parents, even shooting the film in their actual home, but that personal pain doesn’t translate. Where Rose Glass’s Saint Maud turns a similar brew of spiritual fervour and impending death into an astonishing study of religious psychosis, Undertone struggles to swerve hagsploitation tropes. Michèle Duquet has a thankless role as the catatonic mum seemingly there to amp up Evy’s dawning disquiet.  

My prediction is that Tuason will go on to make ingenious horror films, especially with a bigger budget and maybe starting with the Paranormal Activity reboot he’s working on next. This one, though, doesn’t match its rich promise.

In UK and Ireland cinemas Apr 10. In US theaters now.