This Toronto director filmed the horror movie Undertone in his childhood home

Get two lively hosts behind the mic of a creepy podcast that records at 3 a.m., add a dash of ancient demon mythology and a heavy dose of Catholic guilt and you’ve got Undertone, writer-director Ian Tuason’s new A24 horror flick, out on streaming platforms April 14. It centres on Evy (Nina Kiri), a recovering alcoholic temporarily living in her childhood home while caring for her dying mother. She has one hobby: co-hosting a ghost-story podcast with her friend Justin, who plays the believer to her skeptic. But her apprehension spirals into a nightmare when they receive haunted recordings from an anonymous sender that begin to torment her late into the night.

Tuason, a lifelong Torontonian who is “just so proud the TTC reaches Rexdale now,” studied creative writing at York University before working in sound design and then film. Like Evy, he hosted a true crime podcast, and in 2020, he began caring for his parents in his childhood home as they battled cancer—the very same house where he shot the film. We caught up with Tuason to talk about the bidding war that erupted over his film, being tapped to direct the new Paranormal Activity and how making a horror movie can be oddly therapeutic.

What’s the origin story of Undertone? Before the pandemic, I started writing it as a radio play where two podcast hosts talk about creepy found audio footage. There’s a bunch of similar ones that exist—like Homecoming or The Black Tapes. My parents got sick in 2020, and I moved to their home in Rexdale to start caregiving full time. I began to envision a film about possession over a caregiver. When I revisited the podcast material, I asked myself what the main character, Evy, might be doing between recording sessions. Then I intertwined the two stories. No studio was interested in the script, but when I received a small inheritance from my father, I decided to use it to make the movie. When producers found out I was going to make my film, my way, with my own money, they got FOMO and finally read the script. Even with the help of some friends’ investments, it was still a tight budget, so we shot it in my childhood home to save money.

We finished the final cut two days before our premiere at Montreal’s Fantasia festival. Afterward, audience members went online and posted about how scary it was. The biggest studios started emailing me and my team asking for screeners. I didn’t respond because I was exhausted. It felt like suddenly half of Hollywood had watched it, and that led to a high-stakes bidding war for distribution. A24 won—and they were my top choice.

Undertone seems to haunt the ears as much as the eyes. How did you build the sound design? I got my audio experience in designing 360-degree soundscapes for virtual reality headsets. I had to think about sound as very directional—where it originates, where it travels and what that evokes. I worked with Toronto’s Red Lab, which has done post-production for lots of great Ontario-based productions like Schitt’s Creek. I gave the mixer, John Wallace, a list of sounds, and we figured out where to place them. Some of the sounds feel like they come from behind the viewer. Others build from below until they become unbearable.

The house is filled with Catholic paraphernalia. What’s going on there? We are all haunted by shadows in our unconscious. As I was writing Undertone, I discovered that I had been hard on myself while caring for my parents because of, well, conditioned Catholic guilt. I was always questioning myself. Am I good? Am I doing this well? I was plagued by doubt but also felt guilty for doubting myself. The message is that the terror that guilt and doubt produce is real—whether that demon exists outside of you as a supernatural force or inside of you as a psychological one, it’s the same experience.

Related: Sarah Gadon on the creepy brilliance of Wayward

Was filming in your childhood home, where you had cared for your parents as they battled cancer, emotionally challenging? It was nothing. Grieving the loss of both parents is so difficult that, afterward, I realized, nothing will ever be so hard in comparison. It was therapeutic to work with Nina Kiri, who plays the Evy, because she understood what I’d endured. She tapped into the part of me that’s in her and portrayed it back to me. It made me feel like I wasn’t alone.

At the end of the film, there are scary childish drawings covering the walls. Our props person said they were kind of cute. She wasn’t wrong. There was something comforting about reframing them that way. After the shoot, I painted the walls the same blue as the evil eye—the symbol of protection.

You had a tight cast—it’s arguably a one-woman show. What were some of the perks of working so minimally? Constraints are a necessity to creative freedom. I’m a Libra, so I’m always trying to weigh every possibility until eventually I can’t choose anything. It’s better to have fewer options and to make decisions quickly. Your first instinct is usually the best choice, and beyond that, extra options just add confusion.

As a fellow spooky Canadian, what are your thoughts on David Cronenberg? I love Cronenberg. The Fly is currently a big influence for an upcoming sci-fi horror I’m working on. I’m inspired by a handful of other horror directors as well: Kubrick for his symmetry and use of silence as a scare tactic, and Hitchcock for all that detailed planning. There’s also a direct reference to Danny Boyle’s Sunshine in Undertone, if anyone can spot it.

Related: David Cronenberg’s creepy obsessions say as much about us as they do about him

Are you particularly loyal to any Toronto cinemas? Imagine Cinemas on Front Street is cool because the walls are covered in black-and-white photos of old Toronto theatres from the ’40s and ’50s. But, for sentimental reasons, I endorse the CineStars Deluxe in the Woodbine Mall. It’s small and scrappy, and it’s where I watched Batman, Teenage Mutant Ninja Turtles and Short Circuit growing up. It’s also where I first had my heart broken, when the theatre stopped the projection of Batteries Not Included mid-screening due to a flood.

Speaking of iconic films, you’re also writing and directing Paranormal Activity 8. How are you planning to add your own spin on the franchise? I’m a big fan of the first three movies in the series, so I’ve been figuring out what makes them better than the others and trying to bring more of that back. I’m also seeing the tech—the cameras the characters set up to document the supernatural presence—as having a personality of its own. But the biggest goal for me is to use the audience’s imagination as a tool. The scariest monster one person imagines is different from that of person next to them, so I’m harnessing that uncertainty for maximum scare factor.

Anything else on deck for you? I’ve been spending every morning writing because I’m in late-stage talks for two sequels to Undertone. All of the questions everyone has about Undertone will be answered in the next two editions—that’s the best I can do for a teaser.

This interview has been edited for length and clarity.