Yes, it is free to use the 39 Clues website.
There are absolutely no cheats for the 39 clues website. AT ALL!
The title of the seventh 39 clues book is The Viper's Nest. My agent Code is P2J34GKXXP on the 39 clues website.
The name of the eight 39 clues book is The Emperor´s Code. my agent code on the 39 clues website is P3XDKTN9XP
No you can't be a madrigal if you created an account on the 39 clues. Trust me I tried it once.
the books will only give you ten clues so the cards fill in the gaps along with the 39 clues website
The 39 clues is about the Cahill family which is the most powerful family in this world. They have the power to rule the world. The 39 clues is a hunt for the 39 clues that can make a person the most powerful person in the world. These books have cards with unique codes that can be used in the hunt for the 39 clues on the official website.