The Lost Hero by Rick Riordan
The Lost Hero was a really good read that goes along with the Percy Jackson series. In the Lost Hero Percy Jackson is no were to be found and there is a new hero that has no idea what is going on since he has lost all of his memory. This new hero, Jason, and his friends most go on a quest to find the missing goddess Hera. They must find her by the winter solstice to stop the prophecy from coming true. This prophecy reveals that the Greek gods maybe defeated by someone even older and more powerful than themselves.