The adventure unfolds in this third book in the bestselling Seven Wonders series!

Jack McKinley and his friends defeated the Colossus of Rhodes, unearthed the treasures of the Hanging Gardens of Babylon, and recovered two of the seven lost Loculi—only to find that they'd been betrayed by one of their own.

With Babylon in ruins, Marco on the Massarym side, and long-held secrets coming unraveled, the kids don’t know who to trust. Their G7W powers are manifesting at a furious pace. They have no choice but to continue their quest, to the most terrifying of all the Wonders.