Urianger makes some progress toward a solution, but when you reach an impasse, Jeryk gives a reluctant explanation.
This quest is available if you have completed the quest Down for Maintenance.
Starting the Quest
Talk to Jeryk in Amh Araeng to begin the quest.
Speak with Thaffe
Go south into the bar (where Sveinn and Tofrith are on the porch) and talk to Thaffe to proceed. There will be a cutscene. This one is important, so it is recommended to watch it either now or via the Unending Journey in an inn room.
Speak with Urianger
Talk to Urianger to proceed.
Search for Thancred
Go east to the orange circle on the map. Go to the southeast edge of the orange circle and talk to Thancred to complete the quest.
Aether Current Quest
With the completion of this quest, you can now start the blue quest "Charmless Man" in Amh Araeng. Completing that quest will attune you to an Aether Current in this area.
Next Main Scenario Quest
After you complete the quest, you will need to be at least level 77 to proceed to the next quest. After you reach level 77, talk to Thancred to accept the next quest: A Convenient Distraction.