At the end of Undertone , things deliberately stay ambiguous, but there are some clear clues about what’s happening to Evy and her family.

Quick answer

The final audio file completes a ritual that lets the demon Abyzou fully cross over, Evy’s house mirrors the tapes’ haunting, the screen cuts to black as her mother moves unnaturally and the baby cries, strongly implying that Evy and/or her mother are taken or killed while the baby is left alive as the demon’s new “vessel” or legacy.

How the ending plays out

  • Evy and Justin decide to play all 10 mysterious audio files on their podcast, even after realizing they’re tied to a real couple who died at the bottom of the stairs with baby drawings on the walls and a dead child involved.
  • As they go deeper, sounds and events from the recordings start to echo inside Evy’s actual home: thuds, nursery rhymes, footsteps, and patterns matching the haunted couple’s story.
  • Research links the phenomenon to Abyzou, a child‑stealing demon tied to pregnancy, dead children, and generational guilt.
  • By the final recording, Evy’s reality is synchronized with the tapes: the house layout, the stairs, and the sense that she’s re‑enacting someone else’s nightmare.

In the last sequence, the power cuts, strobe‑like lighting and distorted sound take over, her mother begins to move as if controlled by something else, and we hear layered baby cries as Evy screams “No!” before the film abruptly cuts to black, leaving only sound to suggest what happens next.

What most people think “actually” happened

Different viewers read that blackout differently, but three big interpretations dominate forum and video breakdowns.

  1. Literal demon possession (most popular)
    • The 10 audio files are a ritual: playing them in full “opens the door” for Abyzou to enter Evy’s house.
 * The demon first uses Evy’s mother as a host (explaining her strange movements), then kills Evy and the mother, leaving the baby alive and spiritually claimed.

 * The ongoing baby cries after the blackout support the idea that the child survives, but not in a safe way.
  1. Psychological collapse / no real demon
    • Some argue the film is about caregiver burnout, pregnancy dread, and religious guilt; the “possession” is Evy’s mind breaking under pressure.
 * In this reading, the house noises and “ritual” are projections of trauma; the cut to black is her complete mental break rather than a supernatural event.
  1. Time‑loop / “closed loop” theory
    • A popular fan theory says Evy herself (possibly in the future or in a corrupted digital form) is the one who sends the audio to her past self, trapping her in an endless cycle of trauma and haunting.
 * The “frequency handoff” idea: the ending is less a death and more a transformation, where the entity’s presence moves fully into the bloodline/child via sound.

Why the movie cuts to black

The director leans into an A24‑style “elevated horror” move: take you right to the brink of the reveal, then shut off the visuals and force you to listen.

  • Cutting to black keeps the ending open‑ended: you never see a body, only hear cries, footsteps, and Evy’s last scream.
  • The sound‑only finale matches the film’s core idea that horror travels through audio, podcasts, and shared stories.
  • It also makes the audience complicit: by listening all the way to the end (like Evy did), you’ve “completed” the ritual in a symbolic way.

So, what happened at the end of Undertone?

Putting all the clues together, the cleanest read is:

  • Evy ignores all the warnings and finishes the 10‑file sequence on air.
  • Doing so completes a demonic ritual tied to Abyzou and child‑related tragedy.
  • The demon crosses from the recordings into her home, likely possessing her mother and then claiming Evy as well.
  • The baby survives physically, but the final cries and “frequency handoff” imply the entity has attached itself to the child, continuing the cycle of generational horror.

The film refuses to spell this out visually, so you’re meant to walk away unsettled, still arguing about whether you just watched a haunt, a breakdown, or a curse that never ends.

Information gathered from public forums or data available on the internet and portrayed here.