Alison Wilde is an ordinary girl in a nearly normal world, until a turn of events shifts her reality upside down. Plunged into the Netherworld, with little memory of her life back on Earth, she is faced with a host of fantastical creatures, some more familiar than others. But as her new companions attempt to guide her through their tumultuous realm, dark forces threaten the very fabric of the Universe, who will stop at nothing to prevent Alison from achieving the potential her destiny holds.