When the Horde was driven back into the Black Morass, we were able to only take a small portion of our forces through the Dark Portal before it was destroyed. With the Dragon Queen Alexstrasza rescued and the Dragonmaw clan captured by the Alliance, we were no longer able to command these great winged beasts.
While securing the rift and beginning construction of a new portal, your encampment is approached by a haggard Grunt. His uniform marks him as a warrior of the Bleeding Hollow. He tells how those of his clan who did not return through the Portal have eluded capture and imprisonment by the Alliance armies. You also learn that many of the Dragons that were once enslaved have continued to feed upon Humans and are now roosting at Blackrock Spire. If you can break through the Human defenses and gain the trust of these creatures, perhaps you can bring Ner'zhul powerful allies.
Capture as many dragons as possible
Capture the dragon roost nestled high in the mountains