Temple of Atal'Hakkar (Sunken Temple) 50-55

Before Entering the Instance

Go to the Marshal’s Refuge area of Un’Goro Crater and talk to Muigin to start Muigin and Larion, which leads to A Visit to Gregan, which leads to Haze of Evil

Go to the Broken Pillar area of Tannaris and talk to Marvon Rivetseeker to start Into the Depths and Secret of the Circle

Go to the Dwarven District area of Stormwind and talk to Brohann Caskbelly to start In Search of The Temple, which leads to To The Hinterlands, which leads to Gryphon Master Talonaxe, which leads to Rhapsody Shindigger, which leads to Rhapsody's Kalimdor Kocktail, which leads to Rhapsody's Tale, which leads to Into The Temple of Atal'Hakkar

Go to the Shadra’Alor area of the Hinterlands and talk to Atal'ai Exile to start Jammal'an the Prophet

Go to Steamwhedle Port in Tannaris and talk to Yeh'kinya to start Screecher Spirits, which leads to The Prophecy of Mosh'aru, which leads to The Ancient Egg, which leads to The God Hakkar

Class Specific

Paladins go to the Cathedral in Stormwind and talk to Lord Grayson Shadowbreaker to start Chillwind Point, which leads to Dispelling Evil, which leads to Inert Scourgestones, which leads to Forging the Mightstone

Druids go to The Park area of Stormwind and talk to Theridran to start Torwa Pathfinder, which leads to Bloodpetal Poison, which leads to Toxic Test, which leads to A Better Ingredient

Hunters go to The Military Ward in Ironforge and talk to Olmin Burningbeard to start The Hunter's Charm, which leads to Courser Antlers, which leads to Wavethrashing, which leads to The Green Drake

Inside Instance

Go to the Chamber of the Dreamer in the Temple of Atal’Hakkar (Sunken Temple) and kill the Shade of Eranikus to start The Essence of Eranikus