"What would happen if you discovered that your family was one of the most powerful in human history? What if you were told that the source of the family's power was hidden around the world, in the form of 39 clues? What if you were given a choice -- take a million dollars and walk away ... or get the first clue? If you're Amy and Dan Cahill, you take the clue -- and begin a very dangerous race."--Back cover.

In the first 39 Clues book, Amy and Dan Cahill discovered that they're part of one of the most powerful families in human history. Passing up the hush money, the siblings set out to uncover the 39 clues which would reveal the source of their family's awesome power. In each subsequent book, the siblings attempt to discover one clue at a time. Here, in the fifth book, Amy and Dan find themselves on their most dangerous adventure yet as they investigate...

Amy and Dan travel to a distant land to follow in the footsteps of their most formidable ancestor yet, a military leader who teaches them the art of ancient warfare.