The Sea of Monsters by Rick Riordan
Also by this author:
The Lightning Thief
This book is recommended for advanced readers in fifth grade and up
This is the second book in the Percy Jackson series. If you've ever wondered what it might be like to destroy the school gym with a game of dodge ball where your opponents are giants throwing fireballs, you might like this book (and that's just Chapter 2).
This is another action-packed book in this best-selling, sprinkled with age-appropriate humor. Fans of the first book, The Lightning Thief, are sure to tear through this book just as quickly.
Book Advisory Information: Use of Weaponry, Violence, Use of Magic