Mount Hyjal is a level 80-82 contested zone opened up for general access in the Cataclysm expansion. Hyjal is under heavy siege by Ragnaros, who is trying to destroy the World Tree, Nordrassil. Malfurion Stormrage has returned from the Emerald Dream, and commands the armies of Cenarius, known as the Guardians of Hyjal. The zone makes extensive use of the terrain phasing technology.

For years, Mount Hyjal and the wounded World Tree, Nordrassil, remained cut off from the rest of Azeroth. Sealed away within a protective field of dense foliage by Malfurion Stormrage, Nordrassil has been slowly recovering from the devastation of the Third War, when Malfurion called upon the tree's power to destroy the archdemon Archimonde and repel the forces of the Burning Legion and Scourge. Now, with the cataclysm, the World Tree's well-being is threatened once more. From the Firelands within the Elemental Plane, Ragnaros and his minions prepare to burst into Hyjal and set Nordrassil ablaze -- and the conflagration would endanger all life on Azeroth.