This quest is not available in game.
Kill High Inquisitor Whitemane, Scarlet Commander Mograine, Herod, the Scarlet Champion and Houndmaster Loksey and then report back to Raleigh the Devout in Southshore.
I once served the Scarlet Crusade with honor, loyalty and pride. I believed their cause to be a noble one: to rid Azeroth of the undead.
But as I spent time at the Monastery in Tirisfal Glades I realized that their grasp on reality was slipping. They now think everyone is plagued who doesn't wear the tabard of the Crusade. Innocent men and women were tortured because they were supposedly plagued.
The Scarlet Crusade must be crushed in the name of the Light. You, <name>, must destroy the deranged regime.