The A24 logo and the unsettling, grainy images.

The ad opens with the A24 logo, followed by a woman wearing headphones in a dimly lit room, speaking into a microphone. The scene transitions to close-ups of the microphone, then to unsettling, grainy images of children and a figure in a uniform. A phone call notification appears on a screen, followed by file names like 'tenel', 'One.mp3', '3hree.mp3', and '4our.mp3'. The woman looks increasingly disturbed as she listens. A clock shows 3:00. A black screen displays the quote "THE SCARIEST MOVIE YOU'LL EVER HEAR". A dark hallway with a cross on the wall is shown, followed by a distorted reflection of a person. Another black screen displays "AN UNHOLY TERROR". A wheelchair is visible in a dimly lit room. A final black screen reads "THE YEAR'S FIRST GREAT HORROR MOVIE". The woman's face is shown in extreme close-up, looking terrified. The screen goes black, then displays the title "undertone" with a sound wave graphic. The ad ends with "IN THEATRES FRIDAY GET TICKETS NOW" and logos for A24, TELEFILM CANADA, and UV FILMS.