Undertone is a 2025 Canadian supernatural horror film written and directed by Ian Tuason in his feature debut, picked up for distribution by A24, and built around the unsettling concept of a paranormal podcast host who begins receiving terrifying anonymous audio recordings. Made on a modest five hundred thousand dollar budget, the film went on to gross twenty one million at the box office — a runaway success that earned its reputation honestly.

For context, I've watched a significant amount of horror this year, including most of the Conjuring universe and a steady stream of A24's recent output. None of those films gave me the kind of sustained physical reaction Undertone produced. This film operates on a frequency many horror films aim for and few actually achieve.

The genius of the film is its commitment to sound as the primary engine of terror. There are very few traditional jump scares. Blood and gore are largely absent. What Undertone offers instead is something more insidious — a creeping, all-consuming paranoia that builds across its runtime until you find yourself convinced that something is about to happen in every single frame. The film exploits your own imagination against you, and it does so with remarkable patience.

The visual language reinforces the atmosphere beautifully. The use of one-shot takes, deliberately slow zoom-ins, and wide compositions that linger long enough for your eyes to start scanning every corner of the frame creates a sustained state of bracing. You spend the entire film preparing for something — and whether that something arrives or not, the preparation itself becomes the horror.

This is what good genre filmmaking looks like. It trusts its audience. It understands that what your brain conjures in the silence is often more frightening than anything a film could show you. And it uses sound — sound — as both weapon and accomplice throughout.

A strong entry in the modern A24 horror catalogue, and a director worth keeping an eye on.