The 39 Clues Wiki
The 39 Clues Wiki
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All the 39 clues

About the Clues

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 Clues


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 Combos

The Clues Online

Clue Chart

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

List of Clues

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

This is the Madrigal crest you find in your 'My clues' page in next to clue 39 that means you're able to complete mission 10:end game

False Clues

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."