d nation in the Indian Ocean, the explorers venture through a vast underwater world and take part in a friendly robotics competition. But the tides of good fortune change quickly.

Suddenly, Team Cousteau jumps into action to rescue a faculty member from the brink of disaster. Meanwhile, the team follows Cruz's mother's clues to a magnificent tomb and center of spirituality precariously perched on the side of a cliff. There, Cruz is confronted by a familiar foe who's determined to stop him from completing his most important mission of all: retrieving the final pieces of his mother's cipher. In this life-and-death showdown, Cruz witnesses the ultimate sacrifice and uncovers a hidden message that makes him question his own mortality.

The paperback edition includes the same great content and back matter as the original hardcover.

And don't forget to check out the other books in the series:

• Explorer Academy: The Nebula Secret (1)
• Explorer Academy: The Falcon's Feather (2)
• Explorer Academy: The Double Helix (3)
• Explorer Academy: The Star Dunes (4)
• Explorer Academy: The Dragon's Blood (6)
• Explorer Academy Future Tech
• Explorer Academy Field Journal
• Explorer Academy Ultimate Activity Challenge
• Explorer Academy Codebreaking Activity Adventure
  

Praise for the series:

"This exciting, fast-paced, far-flung story is full of science facts and James Bond-like gadgets, accompanied by colored illustrations. The ending is guaranteed to keep readers eager for the next series installment." -Booklist

"...a fully packed high-tech adventure that offers both cool, educational facts about the planet and a diverse cast of fun characters." -Kirkus Reviews

"A fun, exciting, and action-packed ride that kids will love." -J.J. Abrams

"I promise: Once you enter Explorer Academy, you'll never want to leave." -Valerie Tripp