Bring the Nightmare Shard to Hamuul Runetotem on Elder Rise.
This shard holds great secrets; it is the pure essence of the Emerald Dream. However, what I see in this shard is not a dream; one would call this sort of a vision a nightmare.
I do not wish to alarm you, [player], but I think it is best if you deliver this shard into the hands of a wise druid as soon as you can.
Hamuul Runetotem on Elder Rise is who you need to find. Head to Thunder Bluff. I cannot say more.