Ragefire Chasm

From the introduction:

Ragefire Chasm extends deep below the city of Orgrimmar. Barbaric troggs and devious Searing Blade cultists once plagued the volcanic caves, but now a new threat has emerged: dark shaman. Although Warchief Garrosh Hellscream recently called on a number of shaman to use the elements as weapons against the Alliance, the chasm's current inhabitants appear to be renegades. Reports have surfaced that these shadowy figures are amassing a blistering army that could wreak havoc if unleashed upon Orgrimmar.

The adventurers have been sent to Ragefire Chasm to investigate this potential threat.