This quest is not available in game.
Travel to Blackrock Spire and slay General Drakkisath.
We battle against these beasts on two fronts: From our capital of Stormwind we fight them from the inside out and here, in the Burning Steppes, we take the battle to their doorstep. We must be vigilant, <name>. None should be spared our wrath as none of our own were spared when they struck at our homes and families.
Find this General Drakkisath and destroy him!
The task certainly will not be a simple one, but the rewards shall be extravagant.