We recently came upon schematics that indicate a weakness in Icecrown Citadel. An opening in its defenses, both figuratively and literally.
The captured diagrams show an orifice leading several hundred feet into the ground. We're unsure of its purpose, but our scouting has revealed it to be of high importance to the Scourge.
Speak to Sergeant Kregga below Icecrown Citadel, she's leading the attack on the site.
Kregga is found under Icecrown Citadel, there are holes down to the area on each side of the main staircase leading to the Citadel proper.