Heather Worth thinks she is just a regular kid who loves narwhals, drawing maps, and playing spy like her favorite book character, Herry. What she doesn't know is that her entire childhood has been engineered by a shadowy intelligence organization that relocated her family to Ossian, Indiana, to monitor a strange boy named Chase — a boy whose skin seems to glow from the inside and who carries a mysterious, painful presence he calls Hurty. As Heather grows from a bright-eyed kindergartener into a sharp, curious third-grader, the lines between her innocent games of make-believe and the very real, very dangerous world her parents inhabit begin to blur in ways that no one — not her handlers, not her parents, and certainly not Heather — is prepared for.