When high school senior Gabby Spencer's twin brother Devon mysteriously disappears from their quiet home in Kentland, Indiana, she and her family are devastated; but when she meets Julius Carter, the new guy at school, she quickly gets some much needed answers about Devon - whether she likes them or not. With Julius's help, Gabby learns that she and her brother are part of an ongoing battle between Heaven and Hell, and that not only is she not entirely human, but that the fate of the earth is in her hands. Will Gabby be able to fulfill her destiny and save the earth from the torturous grips of Hell? Or will the unconditional love she feels for her twin brother prevent her from eliminating him?