Mount Hyjal quests

Mount Hyjal is one of the two 80-82 level-up zones in Cataclysm. Breadcrumbs come from Stormwind and Orgrimmar from the Hero's Call and Warchief's Command billboards, which send players to Moonglade. There, the breadcrumb As Hyjal Burns directs players to the zone, where the chain proper starts underneath Nordrassil, the world tree, with Inciting the Elements and The Earth Rises.

Hyjal is an extremely-phased directed-questing experience. Following the breadcrumbs from point A to point B will have players explore the zone in a relatively natural progression.

The other 80-82 level-up zone is Vashj'ir. The quest chain of Vashj'ir also starts from the Hero's Call/Warchief's Command billboards and drops players off in Kelp'thar Forest.

The progression of the storyline in this zone is tracked in the achievement Coming Down the Mountain.

After Mount Hyjal, the next zone is Deepholm, which is started at the Earthen Ring earthshrines outside of Stormwind City and Orgrimmar.

After Return to Nordrassil, two quests open up: The Return of the Ancients and Wings Over Mount Hyjal.

After Return from the Firelands, two quests open up: The Fires of Mount Hyjal and Aviana's Legacy.

Completing Egg Wave awards the achievement Beware of the 'Unbeatable?' Pterodactyl.

The first part of Firelands Invasion takes place in Mount Hyjal. For complete Firelands Invasion quest chain, see here.