Oran Snakewrithe in Undercity wants you to travel to the Hinterlands and burn the Highvale Records, Highvale Report, and Highvale Notes.
The Quel'Danil Lodge is a center of communication for the high elves of the Hinterlands. Their ambassadors are working to establish relationships with other races, with whom they share their knowledge of the Witherbark trolls that inhabit the area in the southern Hinterlands. All of the documents regarding the communications are kept at the lodge.
We don't need the Highvale building alliances with others, <name>.
Destroy the Highvale documents. We need to burn their lines of communication... literally.
Perfect, <name>. While the Highvale work to recover their lost information, we will be able to seal off the lines even further...