From a #1 internationally bestselling author comes an atmospheric, chilling novel about a family who thinks there's someone hiding in their attic.

You thought you were home alone.

Anya is enjoying a relaxing bath when she hears a noise coming from the ceiling. Through the open bathroom door, she sees the attic hatch swing down, and a masked figure drops to the floor. Thirty seconds later, Anya is dead.

You're not afraid of being alone in the dark. You're afraid you're not alone.

Across town, Anya's old school friend, Julia, sees an online video of a masked figure climbing out of an attic. She suddenly realizes why the footage is eerily familiar: it was filmed inside her own house in a luxury gated community, designed to keep intruders out.

And now your worst fears are coming true.

Why would a stranger target Julia? Unless of course, it's not a stranger at all.