Bring the Fifth and Sixth Mosh'aru Tablets to Prospector Ironboot in Tanaris.
While I look over the third and fourth tablets of Mosh'aru, you must find the fifth and sixth! It will not be easy, for they are held by the Smolderthorn trolls within Blackrock Spire. The spire is a dark mountain of fire between the Burning Steppes and the Searing Gorge.
Good luck, [player]. Blackrock Spire is no place for decent folk...