Son of Neptune is the perfect next book to The Lost Hero. In this book, we find that Percy Jackson has stumbled into Camp Jupiter, a Roman demi-god camp. But Percy Jackson doesn't know who he is or where he came from. Meanwhile, Gaea's gaining power and trying to raise one of her Titan sons, and she is using Percy as a Pawn in her plan. With the help of his new friends Frank and Hazel, Percy must go on a quest to stop Gaea's son from rising and causing a war between the Greeks / Romans.
Riordan brings back the world of Percy Jackson with a twist. He places Percy on the Roman side. I love the creativeness of this series, and the fact that Riordan mixes both Greek and Roman mythology as though they co-exist. And maybe that's the point he is trying to make with this series.
The ONLY thing I had a problem with with Son of Neptune was Frank and Hazel's back stories. To me they weren't as exciting as Piper and Leo in The Lost hero. All though, Frank's power was kind of cool, I found their stories to move slowly and drag on. But besides that, Son of Neptune was a great second book, and it definitely connected together. I can't wait for Mark of Athena.