Frostmourne Cavern (quest)

Objectives
Zelig the Visionary at Wintergarde Keep in Dragonblight wants you to use Zelig's Scrying Orb at the bottom of Frostmourne Cavern. Unlock the secrets of the past! Provided Item:
 * Secrets of the Past Revealed
 * Zelig's Scrying Orb

Description
They have labeled the cave as Frostmourne Cavern. Why the Scarlet Onslaught is interested by such things is unknown, but by the look of things, the area surrounding the cave is heavily guarded. Nonetheless, we must proceed!

Take this scrying orb and travel north out of town and then northwest towards Scarlet Point. Make your way into the cave and battle your way to the bottom. Once there, use the orb. Return here with what you discover.

Progress
Have you searched Frostmourne Cavern?

Completion
Muradin lives? Could it be? I must notify King Bronzebeard at once!

I need to consult the orb. There must be more information - somewhere!