Clara Hayes finds sanctuary in her new apartment, a quiet corner of a historic building where she can finally breathe. That fragile peace shatters one rain-lashed night when, through the keyhole of her neighbor's door, she witnesses a scene of chilling violence in Apartment 4B.
When she reports it, no one believes her. The police find nothing amiss. The charming tenant, Leo, insists it was just a movie. Even her own therapist suggests it's a manifestation of her past trauma. But Clara knows what she saw. The memory of that fleeting, horrifying glimpse is etched into her mind.
Determined to prove her sanity, Clara begins her own investigation. She discovers the building holds dark secrets, and her neighbor is not who he pretends to be. Each clue pulls her deeper into a dangerous game where the lines between paranoia and truth, between stalker and prey, begin to blur.
Now, the very walls of her home feel like they're watching. Every creak is a warning. To uncover the truth, Clara must confront not only the intruder next door but also the haunting echoes of her own past, before the keyhole becomes a window to her own demise.
