The teaser poster for Undertone wants to be heard ahead of tomorrow’s trailer drop.

The slow-burn horror film premiered at last year’s Fantasia Film Festival, igniting a seven-figure bidding war from which A24 emerged victorious.

Nina Kiri (“The Handmaid’s Tale”) stars as the only on-screen character; a paranormal podcast host who moves into her dying mother’s house to be her primary caregiver.

When she receives audio recordings of a young pregnant couple experiencing supernatural noises, she realizes the woman’s story mirrors her own. Each new recording...