Speak to Senior Sergeant Juktok at Agmar's Hammer.
There remain only two primary threats that stand in our way. One is the dread citadel of Naxxramas, far to the east, above the Alliance fortress of Wintergarde and the other is the Pit of Narjun, exit point for the undead armies of Azjol'Nerub. It is from the Pit of Narjun that the Anub'ar Nerubians assaulted and ultimately razed the taunka village of Icemist.
We will destroy the Anub'ar and close off the Pit of Narjun.
Report to Senior Sergeant Juktok for your mission orders.