For his 18th birthday, Percy is given a quest. Everyone at Camp Halfblood believes he's visiting his Mom, and they have no reason to think otherwise. At least not yet. They don't know that he's stranded halfway across the country with nothing but the clothes on his back. They think that he'll only be gone for a week. But then those seven days eventually turn into 14. When three weeks pass without a single word, Annabeth sets off in search of him. She tracks him all the way to a small town called Beacon Hills, but the boy she finds there is not her Percy.