Lena, the daughter of an Army general, is suddenly taken from school by her best friend, and a guy she barely knows. She's thrust into a world she never knew existed, and ontop of that, he mother, the greek goddess Artemis, needs Lena to save her from the wrath of Hera, whose gems have gone missing. THe only way to do that, is to follow a strange map all across the United States in search of the strange and powerful gems. But is it really only that? Something evil is stirring in the underworld, and Lena and her friends are in the middle of a prophecy that's been told since that beginning of Camp-Half Blood. Is Lena up for the challenge?