Obtain 8 Dalaran Pendants for Shadow Priest Allister at the Sepulcher.
Dalar is attempting to locate the source of the wizards' spellcasting. For now, we'll have to slow their progress in any way we can...
The conjurers, mages and protectors are no doubt carrying the pendants. Remove and retrieve them.
Take the main road south and the eastern fork into Ambermill.