Hour of Twilight is the third and last five player heroic dungeon focused on the final push against Deathwing, released in Patch 4.3.0. It involves escorting Thrall to Wyrmrest Temple in order to put an end to the insane Aspect.
Having shattered the infinite dragonflight and recovered the fabled Dragon Soul, Thrall and his allies must now journey to Wyrmrest Temple and rendezvous with the green, blue, red, and bronze dragonflights. Reaching their destination will be an arduous endeavor: the Twilight's Hammer has amassed its forces near the temple, determined to intercept the Dragon Soul at any cost.
Set in the present-day Dragonblight, it is now under a full invasion by the Twilight's Hammer. Players must escort Thrall and the Dragon Soul safely to Wyrmrest Temple, where the assault on Deathwing is to commence. But the Twilight's Hammer forces are numerous, and their leadership remains strong. Those attacking the temple are commanded by a man known very well for the strength of will he's offered Alliance citizens. Now with his own will broken, he preaches only Deathwing's cataclysmic vision for all life on Azeroth.