This is the final 'main quest' in Blackdagger Ruins (Level 25 quest).
Location: Blackdagger Ruins
Given by: Garl Gnarlclaw
Turn in to: Garl Gnarlclaw
Objective:
BLEEP-BLOOP? ~
As soon as you do the aforementioned. ~ *ADDRESSING THE NEGS*If you play the game and follow the
main questline, doing the dungeons [the red text quests], you can't miss it.
Simply playing the dungeon without being given the quest should net you the achievement.
Also, in 'queues' you should see Blackdagger Ruins as one. (providing you're not level 60 as these are 'epic' versions, which I'm not so sure if they unlock this or not).