Deliver the Sealed Letter to Ag'tor to Ag'tor Bloodfist in Azshara.
Betraying, thieving woman! That's what I call her--that's all she'll ever be!
I may have made a grave mistake, [player]. I trusted a blood elf. What's worse, I trusted a woman!
She claimed Azshara would hold great riches... powerful items. I simply send some warriors with her to protect her and I would be rewarded. Well, look who's the fool--she's killed them all.
I want vengeance, [player], but I can't afford to send anyone else. Find Ag'tor at Valormok, north of the Haldarr Encampment. He'll tell you more.