In Stanton, Kentucky, Halloween has always carried a little magic-but this year, the darkness is answering back. When twelve-year-old Bella Wren and her eleven-year-old sister, Evie, receive a muddy black envelope warning that the legendary Lantern of Black Creek has been stolen, they learn that every shadow in town could soon break free from its owner. Worse, the lantern's blue flame is the only prison holding back the Hollow Walker, a faceless spirit that feeds on fear, loneliness, and borrowed voices. Armed with imperfect spells, a silver bell, emergency cobwebs, and their sharp sisterly banter, Bella and Evie follow a trail of runaway shadows through an antique shop, Black Creek Cemetery, and a hidden world beneath the Kentucky hills. There they discover that Noah Pike, a lonely boy desperate to save his sick younger brother, stole the lantern after the Hollow Walker promised to restore the child's missing shadow. As Halloween midnight approaches and Stanton's shadows rise against the town, the sisters must relight the lantern, free the stolen shadows, and face a creature that knows exactly which fears to use against them. To defeat it, Bella and Evie will have to trust each other, share the cost of their magic, and prove that courage does not mean facing darkness alone.