Go to the new Twilight Camp south of the Blackfathom Deeps entrance on the Zoram Strand of Ashenvale and retrieve Twilight Correspondence from the cultists, then call upon the Earthen Ring Guide using the Totemic Beacon.
While celebration has its place, <class>, some of us must look to graver matters.
When the festival began, we received reports from Zoram Strand about a sharp increase in Twilight Cult activity. The origins of this holiday are steeped in the very powers those madmen revere; this cannot be coincidence. Go to the camp just south of the Blackfathom Deeps entrance, in the ruins, and see if the cultists will part with information - forcefully if need be. Use this beacon to summon a guide when you find it.