This quest is not available in game.
Kill the leader of the Talon Den, Rynthariel the Keymaster.
This scroll is from that scheming dryad Rynthariel, Keymaster of the Talon Den on Stonetalon Peak.
She'll not be making any more contact with the messenger you looted this from, heh, but we must stand our ground here. The Horde will not tolerate her outrunners here.
<name>, travel to the Talon Den. Kill Rynthariel, and then put up a symbol for all to see. Take this Horde flag, <name>. Put it up in the Talon Den so that they will not be so rash as to send another messenger through our territory again.