This quest is not available in game.
Speak with Nathanos Blightcaller.
The Warchief has requested that you return to Orgrimmar as soon as possible. There is an urgent matter that requires your attention. I will fill you in on the details as soon as you arrive. You will find me near the entrance of Grommash Hold. The Dark Lady has plans for you, <name>. I would not keep her waiting...