"Mia covered her mouth to keep from crying out. She hated the dark, but her mother had made her promise. But what was the point of being a good little girl if she couldn't help her mother? She'd promised her mother not to scream, but she hadn't promised not to escape... To the world, Mia Thornton is invisible--a quiet, timid preschool teacher. People would never guess that she found the will to dig her way out of a locked shed when she was just six years old. That she never saw her mother again. Now, all Mia longs for is a normal life and friends to call her own. But when she runs into a group of colleagues one evening, she discovers that, once again, she's been excluded. Stung at the rejection, she pockets the keys of one of the women in a petty act of revenge. Celeste Cooper is fearless, pretty, popular--everything Mia wishes she could be. The next day, Celeste is reported missing. And Mia realizes that it might have been her fault. Wracked with guilt, she joins the search, determined to make up for her mistake. But as she grows closer to Celeste's family, Mia can't help but feel she's being watched... What if Celeste's disappearance has more to do with Mia than she realizes? And if she keeps digging, does she risk being dragged back into the dark forever?"--Provided by publisher.