After the betrayal at the Forgotten Shore, Prince Arthas - with Muradin in tow - began his quest for the . Could the location of the cavern where the Frostmourne found be near? What secrets could it hold? While the orb has no answers for these questions, it does show me something.
To the northeast of Wintergarde Keep is an outpost built by the Scarlet Onslaught. Somewhere within that outpost is a map. The orb tells me that this map will be of great use to us.
Have you recovered the Onslaught map?
A cave? Could it be? There can be no other correlation!
You can find the Onslaught Map at 87.38, which is on table inside the half finished tower in the Onslaught camp.