In 1986, a young woman named Angela lived alone in a small apartment in a quiet neighborhood. One night, while preparing for bed, she heard a faint tapping sound coming from her living room. Thinking it was nothing more than the wind, she dismissed it and went to sleep.

A few nights later, the tapping returned, but this time it was louder and more persistent. Frustrated and unable to ignore it, Angela got up to investigate. As she entered the dark living...