Lucille Masters has spent her nineteen lonely years hating herself for her freakish abilities. When she turned fifteen, she discovered those abilities were somehow connected with an underground world filled with evil creatures who only come out at night to feed from the innocent. After seeing her first vampire, she decided to use her strength and speed to hunt and kill every last one of them to keep her own demons and self-loathing at bay. She now focuses all of her hatred on them. But when the infuriating and bossy Gavin West saves her from a trap set for her by the vampires, she realizes there is much more to this underground world than she ever imagined, and she isn't sure just how deep her connection with it goes. While Gavin seems to confuse Lucy by defying all traits of normal vampires, she soon discovers he may be the only who can help her fend off the much bigger threats closing in all around her.