This quest is not available in game.
Assemble an army and travel to the Eastern Plaguelands. Launch a full assault on Nathanos Blightcaller and any Horde filth that may attempt to protect him.
Keep your wits about you, <name>. The Horde will defend the ranger lord with their very lives.
Do you know how many ranger lords exist in this world? How many human ranger lords have ever existed?
Nathanos' accomplishments were unprecedented. He was a tactical genius, responsible for Alliance victories spanning a decade of conflict.
And now... the champion of the Forsaken.
No. This cannot be. Order must be restored.
Gather an army, <name>. Return to the Plagues with your army and destroy the Blightcaller.
I wish you luck, <name>. Truly, you will need it for this battle.