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.