Beware of Spoilers!

45px The information included in this article appears thoughout the entire 39 Clues universe. 45px

About the CluesEdit

Whoever discovers the great Cahill secret will become the most powerful person (or people) in the world. This secret can be unlocked by assembling all 39 Clues. When combined, these will form the secret--- the Master Serum. Dan and Amy Cahill found all 39 of these throughout the books. All the five branches have a serum(Janus Serum, Tomas Serum, Lucian Serum, Ekaterina Serum and Madrigal Serum). Taking a specific Branch's Serum will give you the qualities of said branch. The serum contains the various Clues of the branch. Assembling all the branches clues gives you the master serum. The Lucian serum was drank by Isabel Kabra. In Book 8, the Janus serum was destroyed. The Ekat serum has been lost for ages. The Tomas serum was drank by Shaka Zulu. For many years, the Cahills believed they were the only ones who knew about the Clues. However, the Vespers --originating from Damien Vesper who used to be Gideon Cahill's friend but killed him-- Also know about them.

How to Get the CluesEdit


There is a mission released for every book.

On the complete of a mission, you get one Clue, except for Mission 10, which grants the player Madrigal status and Mission 11, simply 5 Replicator Cards. However, Mission clues can also be obtained in card combos.


Each book in The 39 Clues comes with six cards. Entering these cards unlocks a Clue except for Vespers Rising and Series 2 and Unstoppable Books.


Certain cards can be combined to make a Clue, and sometimes one card is used in multiple card combinations, also known as card combos. Some Clues only require 1 card, like the Ultra-Rare cards and the CERN and New York Subway cards. Some require you to get different and mutiple cards. These cards are accessible via either replicating

☀Being them, or by using the cards given in a card pack. Cards have different rarities so sometimes more thanbeing 1 card replicator is needed.

Card CombosEdit

The Clues OnlineEdit

Clue ChartEdit

File:Clue1.jpg File:Clue2.jpg File:Clue3.JPG File:Clue4.JPG File:Clue5.JPG File:Clue6.JPG File:Clue7.JPG File:QuartzMini.jpg
File:Clue9.jpg File:Clue10.jpg File:Clue11.jpg File:Clue12.jpg File:Clue13.jpg File:Clue14.jpg File:VinegarMini.jpg File:Clue16.jpg
File:IodineMini.jpg File:Clue18.jpg File:Clue19.jpg File:Clue20.jpg File:Clue21.jpg File:Clue22.jpg File:Clue23.jpg File:Clue24.jpg
File:Clue25.jpg File:Clue26.jpg File:Clue27.jpg File:Clue28.jpg File:Clue29.jpg File:Clue30.jpg File:Clue31.jpg
File:Clue33.jpg File:Clue34.jpg File:Clue35.jpg File:Clue36.jpg File:Clue37.jpg File:Clue38.jpg File:Clue39.jpg

List of CluesEdit

Number Clue Branch Location How to Get Picture
1 Honey Janus United States of America The Founding Fathers Card Combo 50px
2 Hydrogen Ekat Switzerland Cahill Collision Card Combo 50px
3 Silver Ekat Egypt Complete Mission 8 50px
4 Pepper Madrigal Cambodia Madrigal Temple Card Combo
5 Mercury Ekat Croatia Complete Mission 6 50px
6 Wormwood Tomas United States of America The Wild West Card Combo 50px
7 Barley Madrigal Chile The Madrigal Stronghold Card Combo 50px
8 Quartz Tomas Pacific Ocean Secrets of the Deep Card Combo 50px
9 King Cobra Venom Janus India Complete Mission 2
10 Magnesium Tomas North Pole Complete Mission 7 50px
11 Uranium Ekat United Kingdom Complete Mission 0 50px
12 Water Ekat Indonesia "In Too  Deep" Card Pack 50px
13 Phosphorus Ekat United Kingdom (Bermuda Territory) Complete Mission 1 50px
14 Copper Madrigal Madagascar The X- Ray Clue Card Combo 50px
15 Vinegar Madrigal United States of America Buried Secrets Card Combo 50px
16 Gold Tomas South Korea "The Sword Thief" Card Pack 50px
17 Iodine Janus United States of America Frankenstein's Secret Card Combo 50px
18 Iron Solute Lucian France "The Maze of Bones" Card Pack
19 Silk Janus Nepal "The Emperor's Code" Card Pack 50px
20 Myrrh Ekat Egypt "Beyond the Grave" Card Pack 50px
21 Mace Madrigal Jamaica "Storm Warning" Card Pack 50px
22 Bone Tomas Zimbabwe The Missing Explorer Card Combo 50px
23 Rosemary Madrigal United States of America New York Subway Card Combo 50px
24 Aloe Tomas South Africa "The Viper's Nest" Card Pack 50px
25 Sulphur Janus Turkey Turkish Delight Card Combo 50px
26 Calcium Carbonate Lucian United States of America The Desert Mystery Card Combo 50px
27 Salt Lucian United Kingdom The Stolen Clue Card Combo50px
28 Tungsten Janus Italy "One False Note" Card Pack 50px
29 Lead Tomas Venezuela Complete Mission 5 50px
30 Cocoa Tomas Peru The Mountain Challenge Card Combo 50px
31 Serum Formula Madrigal Ireland "Into the Gauntlet" Card Pack 50px
32 Zinc Tomas Russia Complete Mission 3 50px
33 Pearl Janus Germany The Mad King Card Combo 50px
34 Clover Lucian United States of America Complete Mission 4 50px
35 Blood Lucian France Eiffel's Secret Card Combo 50px
36 Platinum Janus Mexico The National Palace Card Combo 50px
37 Amber Lucian Russia "The Black Circle" Card Pack 50px
38 Mint Lucian Morocco Mission 9: The Cliffhanger Clue 50px
39 Lily Madrigal Jordan Sandstone City Card Combo 50px
File:Able to complete end game.jpg

False CluesEdit

Please also see the main article: False Clues


Dan mentions in 'The Maze of Bones' that there could be 39 Clues because "39 is a sweet number. It's 13 x 3. It's also the sum of five prime numbers in a row--3,5,7,11, and 13. And if you add the first three powers of three, 31, 32, and 33, you get 39."

The 39 Clues

The 39 Clues
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