Nothing has felt right since Elle rented out her house. There's a new coldness. Every noise echoes with the thud of a stranger's footstep. The atmosphere is changed. And then there are the darker clues left behind: the message scratched into Elle's writing desk; a tiny shard of glass, wedged into the carpet with deadly precision; fresh fingerprints on the window. I'm in your head. Maybe it's all in Elle's mind? She's a writer - her imagination, after all, is her tool. And yet every threat seems personal. Her own house has become a prison. And now there's no way out. There are secrets, deeply buried, that keep Elle awake at night. Now someone is unlocking her past - and she's given them the key.