Explorer Academy: The Tiger's Nest (Book #5)

On an island 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 centre 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.

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