The Temple of the Jade Serpent is a level 85-86 5-man dungeon found in The Jade Forest. It was introduced with the launch of World of Warcraft: Mists of Pandaria. There is a level-90 heroic and a retired Level 90 Season 1 Challenge Mode version available.
Jade Forest, Pandaria
Sha of Doubt
85 - 86
In the eastern heart of the Jade Forest, the races of Pandaria maintain a temple to the Jade Serpent, a venerable spirit of wisdom and foresight. Here, overlooking Pandaria's coast, the myriad races of the continent come to meditate for insight or peruse the living archives of the temple's library, where Pandaria's history is literally brought to life. The temple is particularly sacred to the fish-like Jinyu, who use its scrying pool to serve as their eyes and ears throughout the continent.
Rising high above the east coast of Pandaria, the Temple of the Jade Serpent stands as a sacred monument to the legendary pandaren emperor Shao Hao's victory over the Sha of Doubt thousands of years ago. Recently, a disastrous conflict in the Jade Forest unleashed the sha, and several of the entities have raided the temple's most treasured stores of wisdom and knowledge.
The dungeon entrance can be found in The Jade Forest. You can enter the dungeon on foot at level 85 for normal, and level 90 for the heroic version. Using the Dungeon Finder, you can specific queue for it with a 358+ Item Level at level 85 to 90, and are eligible to receive it as a random dungeon from level 85 to 87. The Heroic Version requires you to be level 90 to queue for it, with a 435+ Item Level.
As you enter the dungeon, you see a crossroads. You can't go straight because it's blocked off, so you'll need to find another way around. Go left first to meet Wise Mari. Then walk back and go to the right and run into Lorewalker Stonestep to put the scrolls to rest of the sha. Upon coming out from the other side, guards say that their teacher has "betrayed" us and as a matter of fact, she appears before you. Yu'lon appears shortly after to be free of Doubt. Thus, the door swings open and the Sha of Doubt awaits to be dealt with to end the manifestation, once and for all.
The Temple of the Jade Serpent is located in The Jade Forest on Pandaria. The dungeon houses four boss encounters and becomes available to players level 85+ after progressing through the Jade Forest quests. Yu'lon, the Jade Serpent has been driven out of her temple by the Sha of Doubt. To reclaim the temple on her behalf, players must defeat several of the inhabitants of the temple who have been become corrupted before finally defeating the Sha of Doubt.