The 39 Clues Wiki
The 39 Clues Wiki

In the back of many The 39 Clues books, there are advertisements for other book series. These book series include Infinity Ring, Spirit Animals, Tomb Quest, and Shadow House. In Worlds Collide, a fan-written and Admin edited additional book, The 39 Clues characters are mashed up with Infinity Ring and Spirit Animal characters to stop villains from all three series.


39 Clues Shatterproof Cover.jpg

This is the first book that an advertisement appears in. The advertisement is for Infinity Ring.

Trust No One

39 Clues CVV Book 5.jpg

Trust No One also advertises Infinity Ring.

Day of Doom

Day of Doom also advertises Infinity Ring.

Nowhere To Run

Nowhere To Run advertises Spirit Animals.


Breakaway advertises Spirit Animals.


Countdown advertises Infinity Ring.


Flashpoint advertises Spirit Animals.

Mission Titanic

Titanic Card Back.png

Mission Titanic advertises Spirit Animals.

Mission Hindenburg


Mission Hindenburg advertises Tomb Quest.

Mission Hurricane


Mission Hindenburg advertises Tomb Quest.

Mission Atomic

Mission Atomic advertises Tomb Quest.


Outbreak Cover.jpg

Outbreak advertises Shadow House.