For thirteen-year-old bookworm Annie Newman, fitting in has always been a challenge. Her family's move to Willowbrook leaves her feeling even more out of place. The picture-perfect town, her new school, and even her own family seem worlds away from the peace she finds in her books. What starts as an escape from a chaotic family cookout turns into a nightmarish revelation when her younger sister, Emily, goes missing. Desperate to find her, Annie discovers a secret world beneath their home, uncovering dark secrets that lurk beneath the seemingly perfect town. As Annie searches for answers to the horrific events she has witnessed, her journey leads her to terrifying truths about the unworldly forces controlling the idyllic town of Willowbrook. With her warnings dismissed by her family as products of her vivid imagination, Annie races against time to unravel the evil that threatens to destroy her family and find a way out before it's too late.