Jill Lassiter's three-year-old daughter disappears from a playground only to return after forty frantic minutes, but her mother's relief is short-lived--there's a tiny puncture mark on Sophia's arm. Is it a bug bite, as Jill's husband David thinks, or something far more sinister? When doctors can find no trace of drugs in her system, Jill decides she'll never know what happened to Sophia, but at least her child is safe. For now. The Lassiter home, situated in an affluent Pennsylvania suburb, is being watched. Someone has infiltrated the family's professional and personal lives--and is dead-set on making Jill and David face every parent's worst nightmare all over again...and, this time, seems to want more than just Sophia.