When Eleanor Pryce moves into a cliffside house to rebuild her life after tragedy, she expects loneliness. She doesn't expect the knocks at her windows. Or the voice whispering her name through the phone. Or the reflection in the glass that moves a second too late.Something is in the walls.Something that looks back.As sightings spread across town and fear goes viral, the creature behind the glass grows stronger-born from attention, feeding on panic, and learning to imitate the one person it desires most: Eleanor.When Eleanor's sister arrives to help, the entity makes its move. Reality fractures. Reflections come alive. And the only way to stop the thing trying to steal her identity is to deny it the very thing that brought it into the world: A witness.But the whole city is watching now.And once you've seen him...you can never unsee him again.