"We cannot survive without one another" Delilah Christos is missing. And her younger sister, Athena, seems to be the only one who cares. She returns from the hunter academy to her sister's parting gift: a mystery to solve. Delilah knows war is coming and she's got the key to ending it before it begins. But her plans are unraveling and leave her with an impossible choice: save Athena or save the world. Together, the sisters must navigate the ever-treacherous and mystical world of Other, facing the most dangerous creatures known to hell. But they haven't faced the worst danger yet-the secret Athena doesn't even know she's keeping.