From wow.incgamers.com

Quest

Lieutenant Dagel: The Lich King has sent his undead upon our very footstep; we cannot remain idle! Surely you will step up to defend Orgrimmar from these accursed invaders?

There are strange runic circles outside, glowing with the same energy that surrounds the undead and the Necropolis above. They have significance, I'm certain, and I want you to find out what. Thin the numbers of those aberrations while you're at it; bring me proof of their death along with your results, and I will reward you. Go!

Quest Objectives

Collect three Dim Necrotic Stones from the Scourge outside Orgrimmar and investigate the glowing runic circles near their encampment.

Locations

• You can find Lieutenant Dagel (Dwarf) near the inner gate of Orgrimmar, not too far southwest from the spot where Onyxia's head and Nefarian's head are usually displayed on a pole.

• The Runic circle is southwest of the Orgrimmar/Grom'Gol Zeppelin tower. You will find it at the Jaggedswine Farm.

Conclusion

Lieutenant Dagel: Have you investigated the invasion yet? There's no time for dawdling!

Hmm. From what you've told me, the voices within the circles ... they must be used for commuication of some kind. I shudder to think what unnatural minds are contacted through such magic. Regardless, you seem to have emerged whole and sane. The Argent Dawn appreciates your service.