Postmark
Just because you're home -- you think that you are safe. Unless you look at the POSTMARK.

In a quiet Potomac neighborhood, little girls were disappearing. And most terrifying, the children all bore a resemblance to Johanna Hamilton's own daughter, Kirsten.

Detective Dan Whitmore of the Montgomery County police force could not reassure Johanna. Because Johanna kept getting those letters.

But what she didn't know was that someone nearby was watching. Watching her. Watching her daughter.