This quest is not available in game.
Rayne at Light's Hope Chapel in the Eastern Plaguelands will make Dreamwalker Legguards if you bring her the following: 1 Desecrated Legguards, 20 Wartorn Leather Scraps, 8 Cured Rugged Hides and 1 Nexus Crystal.
Many heroes fell in the last war and many continue to perish at the hands of the Scourge to this day. From the corpses of the fallen, the armor is stripped and taken back to Naxxramas to be used for unknown purposes.
Recover the desecrated armor and wartorn armor scraps and supply to me the other material components I require and I will craft Dreamwalker armor.