Son of Neptune, Rick Riordon
Emma
PLEASE READ LOST HERO BEFORE READING THIS POST!

Percy Jackson has "wandered" into the Roman Camp. He has no memory of Camp Half Blood or his life before.
Hazel is a clever daughter of Pluto. She is unsure if Percy can be trusted with her secret - or if she can trust herself.
Frank is a big klutz who still doesn't know who his godly parent is yet. He only hopes to prove himself to Hazel, Percy, and the Romans.
Percy and these new characters discover they are part of the seven mentioned in the prophecy when they embark on another quest to save the Romans and Greeks.
Even though I missed Annabeth and Camp Half Blood, I still loved this book. It was just as good as the other ones, with Percy's friendly, funny voice, as well as Hazel's and Frank's. It also had fun plots and story!