This quest is not available in game.
Speak with Jennea Cannon in Stormwind.
Your knowledge of the craft grows, young <name>. Are you now ready to begin your true lessons? Are you ready to take your place in the secret war we wage?
If so, then speak with Jennea Cannon, in the wizard's sanctum in the mage district of Stormwind. She has a task for you which will open your first window into the invisible world.