The Hidden Word, also known as 'the honey' was a substance used for brain washing within Daedalus' labyrinths.
Daedalus discovered a precious flower known as the White Hellebore. During the construction of the labyrinths, Daedalus and his followers discovered a way to use the flower as a brainwashing substance. In ancient records and wall carvings, the substance is known as 'honey' or the 'Hidden Word'. Daedalus used the flower to create mindless and loyal slaves. However, the process did not always go correctly and often mutate the drinkers - turning them into minotaurs.
Even after Daedalus' death, the servants continued to abduct and brainwash more and more people in order to protect the labyrinths. Led by the Mistress of the Labyrinth, the servants were known as the Protectors of the Hidden Word.
Events in the Fourth Labyrinth
During their discoveries and explorations of Daedalu's labyrinths; Nathan Drake, Victor Sullivan and Jada Hzujak discover the secrets of the White Hellebore. In the fourth labyrinth Tyr Henriksen reveals his true motives - to acquire the last specimens of the flower and sell it to the highest bidder. However, when they reach the centre of the labyrinth Henrisken is killed. The labyrinth is flooded by Nate, and the Hidden Word lost for good.