Arthas and the Scourge devastated the great city of Lordaeron, and the Forsaken are hard at work restoring it. Memories remain in the ruins, heirlooms and keepsakes of loved ones who never made it out, while Scourge still lurk in the darkest corners. Now a necromancer has moved in, and all signs point to an attack on another city.
Blizzard hasn't published the bosses yet. We'll add them as soon as they're known (the beta starts on September 17).