Amy and Dan cross the oceans on the trail of a famous aviator, but they find more than they're looking for. Their enemies are becoming more vicious, and the truths they discover more crushing than ever.
Betrayed by their cousins, abandoned by their uncle, and with only the slimmest hint to guide them, Amy and Dan rush off to Egypt on the hunt for 39 clues that lead to a source of unimaginable power.
Guardians of the 39 Clues, Dan Cahill and his sister Amy discover that the serum is missing and must race against time to get it back before catastrophe strikes.