The host of a popular paranormal podcast becomes haunted by terrifying recordings mysteriously sent her way. A film by Ian Tuason, starring Nina Kiri, Adam DiMarco, Michèle Duquet, Keana Lyn Bastidas, Ryan Turner, Ari Millen, Marisol D’Andrea, Austin Tuason, Seled Calderon, Bianca Nugara, Jayda Woods, Sarah Beaudin, Christina Notto, and Jeff Yung.

Written and directed by Canadian filmmaker Ian Tuason in his directorial debut, undertone is a supernatural horror film centered on Evangeline “Evy” Babic (Nina Kiri), who co-hosts a paranormal podcast called The Undertone alongside her friend Justin Manuel (Adam DiMarco).

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@pradt

undertone 🎧
It wants to be heard.
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A film by Ian Tuason, starring Nina Kiri, Adam DiMarco, Michèle Duquet, Keana Lyn Bastidas, Ryan Turner, Ari Millen, Marisol D'Andrea, Austin Tuason, Seled Calderon, Bianca Nugara, Jayda Woods, Sarah Beaudin, Christina Notto, and Jeff Yung.

Each episode finds the two playing off their contrasting personalities, with Evy as the skeptic and Justin as the true believer, as they dive into all things eerie and unexplained.

Having recently returned to her childhood home in Toronto to care for her comatose mother, Evy records their late-night sessions around the witching hour while Justin dials in from London.

One night, Justin brings up a strange email he received from an address he didn’t recognize, [email protected], with the subject line “LOL beware of listening to all.” The email itself contains nothing but a string of random characters and ten audio files, each with an oddly distorted name: 0ne.mp3, 2wo.mp3, 3hree.mp3, 4our.mp3, 5ive.mp3, 6ix.mp3, 707.mp3, 8i9ht.mp4, 9ine.mp3, and 10 3pm.mp3.

Intrigued but remaining skeptical, Evy suspects the email might be some kind of computer virus. Justin however admits he already clicked on the first file. It turned out to be a phone recording of a young couple. He only listened for a short while before deciding to save it for the podcast.

Justin then starts playing the first audio file. They hear a man talking about his girlfriend Jessa, who has apparently been talking in her sleep. When he tells her about it she doesn’t believe him, so he decides to record her while they sleep. The recording is long and Justin skips ahead to a bump he noticed on the audio waveform, about four hours in. Suddenly they hear Jessa singing “London Bridge Is Falling Down” in her sleep.

“London Bridge Is Falling Down” is a traditional English nursery rhyme and singing game about the repeated collapse and repair attempts of London’s iconic bridge over the Thames River. The rhyme typically starts with “London Bridge is falling down, falling down, falling down / London Bridge is falling down, my fair lady.” It then suggests building materials like wood and clay, iron and steel, or silver and gold, each failing in turn, ending with “Set a watchman to watch all night.” First printed in the 18th century in Tommy Thumb’s songbook, the rhyme likely draws from real events like ice damage in 1281 or fires in 1633 and 1666 that weakened medieval London Bridges.

Justin notes that the audio goes on for a couple more hours but with no other significant bumps on the waveform. He suggests they move on to file number two. In the second file, the boyfriend mentions that Jessa now believes him about the sleep talking. He continues to record her anyway. Justin skips ahead to the bumps and this time they hear bed creaks and the rustle of blankets. It appears the boyfriend wakes up in the middle of the night to find Jessa no longer in bed. Beneath it all they can also make out a strange piece of music playing in the background. Evy recognizes it as “London Bridge Is Falling Down” played in reverse.

undertone premiered at Fantasia International Film Festival on 27 July 2025, where it won the Gold Audience award for Canadian films. It was theatrically released in the United States and Canada on 13 March 2026, by A24.