Book 6 "IN TOO DEEP" has numbers on the plane in the front cover the code for that is "find the other Ekaterina who came too close" Hop that helps
Well,the only card that is from a book that is reuseable is the first card.
There are no cheat code in any game in the 39 clues.
The eighth book in The 39 clues series is 'The Emperor's Code.'
The title of the seventh 39 clues book is The Viper's Nest. My agent Code is P2J34GKXXP on the 39 clues website.
P3rw4fpnxp
kf3x4ttct3
246rp6fxxp
P29rp379xp
water
246RP6FXXF
The Emperor's Code.
the emperor's code
2cwkf3dmx6