The aging orc shaman Ner'zhul has seized control of the Horde and reopened the Dark Portal. His brutal warriors once again encroach upon Azeroth, laying siege to the newly constructed stronghold of Nethergarde Keep. There, the archmage Khadgar and the Alliance commander, Turalyon, lead humanity and its elven and dwarven allies in fighting this new invasion.
Even so, disturbing questions arise. Khadgar learns of orcish incursions farther abroad: small groups of orcs who seem to pursue a goal other than simple conquest. Worse yet, black dragons have been sighted as well, and they appear to be aiding the orcs. To counter Ner'zhul's dark schemes, the Alliance must now invade the orcs' ruined homeworld of Draenor. Can Khadgar and his companions stop the nefarious shaman in time to stave off the destruction of two worlds?
The Second War is over, and Alliance forces have won. They have destroyed the mystic gate that linked Azeroth to the orcs' homeworld of Draenor. Many of the orcs trapped on Azeroth have been rounded up and placed in internment camps. But Small bands of orcs are spotted in the Eastern Kingdoms, intent on claiming certain artefacts for some unknown purpose. Worse, some of the orcs belong to clans never before seen on Azeroth. Somehow the Horde has managed to re-establish the Dark Portal on Azeroth. King Terenas orders the Alliance general Turalyon and the archmage Khadgar to end the orcish threat once and for all. Yet in order to do so, the pair must lead an expedition to Draenor itself. They and their allies must go beyond the Dark Portal before all of Azeroth falls beneath a new and more powerful Horde.