"Dan Cahill is NOT a ninja. But try telling that to him. Especially since he learned that his family--the Cahillfamily--is the most powerful group of people in the world. All he has to do now is to find the 39 Clues hidden around the world that lead to the source of the family's power. That is, if rival family members don't kill him first. Dan better learn how to use his nunchucks. He's going to need them."
A letter to Dan from Grace with a coded message saying "no more launching bottle rockets in my garden".
Preceded by: Card 423: The Hunted
Followed by: Card 425: The Secret Weapon