Speak to Treedin Merrythorn in Rivervale. ( -99, -24, -89 ) Copy/waypoint -99, -24, -89
Search for clues in the The House of Circles. ( -826, -6, -111 ) Copy/waypoint -826, -6, -111
Warning: As you enter, four vale destroyers spawn and attack.
You have to examine three stacks of books. Mouse-over everything in the room to find the interactable book-stacks. After the third clue is found a book NPC will spawn. Hail it and progress through the conversation.