The Lost Hero by Rick Riordan

This book starts a new series in Percy Jackson's world: but Percy's missing. Instead, a new trio of demigods, Jason, who has amnesia, Piper, and Leo go on a desperate quest to rescue Hera before a mysterious, evil force can resurrect one of the giants using Hera's powers. This series is just as entertaining as the original Percy Jackson series, but it adds interesting twists to Percy's world. I can't wait till the next book in this series comes out next fall!