The key to this cage is stored in a pouch over at the worg den, just north of our location. The problem is that the pouch is resting safely atop a tree stump amidst a sea of bloodthirsty man-killing worgs.
You've got one shot to get that key without waking up any of those sleeping worgs. Head to the worg den and find a way into the center. Tread carefully and watch out for the Blackrock worg captain. Get the key and return to me.
If you got a pet, I'd recommend telling it to stay back!