Following the operation at Laxan Loft, you go to Il Mheg, home of the fae folk.
This quest is available if you have completed the quest The Oracle of Light.
Starting the Quest
Talk to Thancred in Il Mheg to begin the quest.
Speak with Thancred
Go northeast to where the orange arrow is pointing in the minimap. Attune to the Aetheryte, then talk to Thancred to proceed.
Search for Looking Grass
Go to the south edge of the orange circle on the map and check on the sparkling Fae Scrub. When you are asked a question, respond with "..." and respond to the second question with "..." as well.
Deliver the Looking Grass
Go to the quest icon on the map and talk to Thancred to hand over the Looking Grass and complete the quest. There will be a cutscene.
Aether Current Quest
With the completion of this quest, you can now start the blue quest "The Forbidden Lran" in Il Mheg. Completing that quest will attune you to an Aether Current in this area.