This quest was marked obsolete by Blizzard and cannot be obtained or completed.
Speak with Regthar Deathgate.
A warrior of the Horde, Regthar Deathgate, is recruiting agents for a mission into the land of Desolace. Speak with him if you wish to volunteer. He is stationed in the Barrens, in a series of bunkers west of the Crossroads.
And sharpen your weapons. Desolace is a place torn by war.