When Jill Lassiter's young daughter disappears from a playground, only to return after 40 frantic minutes, her relief is short-lived, as there's a tiny puncture mark on Sophia's arm. Jill accepts she'll never know what happened, but at least her child is safe. Except Sophia isn't. Someone is watching the Lassiter home. Three months after the incident at the park, Sophia disappears again, and Jill discovers that someone doesn't just want Sophia - they want to destroy the entire family.