Report to Plexi at Invasion Point: Cataclysm.
Now that we have access to the Legion's base at Invasion Point: Cataclysm, we need to figure out a way to shut down their operations there. Wildhammer Stronghold won't be safe until the Legion's presence is erased from Shadowmoon Valley.
I've sent an advance party up to the invasion point to help you formulate a plan to destroy the Legion's supplies. Go back to Legion Hold and step into the teleporter with the green crystals above it. Plexi will meet you at your destination.