Margaret Quinn lives alone, quietly mourning the disappearance of her only child, who fled ten years earlier to join a radical student group known as the Angels of Destruction.

On a cold winter’s night, a nine-year-old girl arrives on Margaret’s doorstep, claiming to be an orphan with no place to go. This child beguiles Margaret, and together they hatch a plan to pass her off as her newly found granddaughter, Norah Quinn.

Their conspiracy is made vulnerable by Norah’s magical revelations to the children of the town, and by a lone figure shadowing the girl, who threatens to reveal the child’s true identity and purpose. Who are these strangers really? And what is their connection to the past, the Angels, and Margaret’s long-missing daughter?