|Appears In:||Mission 6|
The true reason of the fight between the two legendary inventors Thomas Edison and Nikola Tesla was because they were both Ekaterinas looking for one of their branch's lost Clues, and their competitive nature got the best of them. One of them (Nikola Tesla) had a breakthrough, so he hid the Clue in his secret lab in Croatia.
KeyA lightning bolt
This Clue can be unlocked in Mission 6: The Mad Scientist's Clue or by completing the following card combo:
- Card 81: Leslie D. Mill
- Card 98: Thomas Edison
- Card 100: The Sabotaged Lab
- Card 106: Nikola Tesla
- Card 119: Airport Security
Mercury was usually used in thermometers, but now it isn't used because it is highly poisonous and may cause death. This element is one of the two elements that are liquid at room temperature, along with bromine. It has the atomic number of 80.
The cutscene shows Nikola Tesla's Croatian home. Two bulbs on the left and right side start to build up electricity until blue light flies outwards from them. The screen flashes to the word 'MERCURY' and the branch crest, and then they fade.