This is the fourth in Percy Jackson series, and it was my favorite of the books so far. The characters, especially Percy, seemed a little too precoscious in the first books. But now it's like the characters have caught up with their true ages.
This book has Percy and his friends setting off into the Labyrinth in an effort to stop Kronos and his army from gaining access to Camp Half Blood. The adventures are a lot of fun, and the dangers are written well enough to keep you turning the pages.
Ella and I have one book left in the series, and then we'll probably be moving on to Riordan's next series, which deals with ancient Egypt.