Whistle, the latest horror film from The Nun director Corin Hardy, has officially earned an R rating for “strong violent content, gore, drug content, and some language.”

Recently acquired for U.S. distribution by Independent Film Company and Shudder, Whistle leans into Hardy’s signature brutal style, following in the footsteps of his work on The Hallow and the ultra-violent series Gangs of London.

The film centers on a cursed Aztec Death Whistle—an ancient artifact known for its eerie, shrieking sound. When a group of high school misfits blows the whistle, they unwittingly summon their own deaths. As bodies begin to fall, they race to uncover the whistle’s origins in a desperate bid to break the curse.

The cast includes Dafne Keen (Logan, The Acolyte), Sophie Nélisse (Yellowjackets), Sky Yang (Rebel Moon), Percy Hynes White (Wednesday), and Nick Frost (Shaun of the Dead).

Written by Owen Egerton (Blood Fest, Mercy Black), Whistle is based on his own short story. The film is produced by David Gross (Room) for No Trace Camping and Macdara Kelleher (The Pope’s Exorcist) for Wild Atlantic Pictures, with Black Bear handling international sales.

“Whistle is made with the same heart-on-sleeve, disenfranchised-teen spirit found in my favorite genre movies growing up,” Hardy said. “The mysterious mythology of the Death Whistle gave me a chance to explore imaginative, cinematic, and terrifying deaths.”

With its rating now confirmed, a trailer and release date are expected soon. Stay tuned.