This quest is not available in game.
Archmage Angela Dosantos at Light's Hope Chapel in the Eastern Plaguelands wants 5 Arcane Crystals, 2 Nexus Crystals, 1 Righteous Orb and 60 gold pieces. You must also be Honored with the Argent Dawn.
In the thick of Plaguewood lies the entrance to the dread citadel of Naxxramas. Previously, all attempts to enter had been stymied by the magical wards placed upon the rune portal. That is, until now.
We have devised a way to gain entry via arcane cloaking - an old cantrip of the Kirin Tor with a few modifications of my own. Since your dedication to the cause of the Dawn is somewhat lacking, <name>, the price will be high. You may decline and choose to return when you are revered or exalted for a discount.