Your pursuit of Vauthry has led to unexpected events in Eulmore and Kholusia. You consult with Thancred about how to proceed.
This quest is available if you have completed the quest A Feast of Lies.
Starting the Quest
Talk to Thancred in Eulmore to begin the quest.
Search for Enthralled Civilians in the Derelicts
You can now attune to the Eulmore Aetheryte. Attune to it if you have not yet done so, then use it to go to the Nightsoil Pots. Go to the west side of the orange circle and check on Thoarich.
Administer Dream Powder to Thoarich
Target Thoarich, and then you can either examine or target him and use the Dream Powder on him from the Key Items section of your inventory, or you can target him and use the icon to the right of the quest name in your list of active quests.
Search for Enthralled Civilians in the Understory
Use the Aethernet Shard to go to the Mainstay, then go up the nearby stairs and check on the Amiable Maiden.
Administer Dream Powder to the Amiable Maiden
Use the Dream Powder on the maiden the same way as described above.
Search for Enthralled Civilians in the Canopy
Use the Aethernet Shard to go to the Eulmore Aetheryte Plaza. Go to the north part of the orange circle on the map and check on the Free Citizen.
Administer Dream Powder to the Free Citizen
Use the Dream Powder on the free citizen the same way as described above.
Speak with Ryne
Go west until you can go south to the Aetheryte Plaza, then go southeast from the Aetheryte and talk to Ryne to complete the quest. 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.
Next Main Scenario Quest
After you complete the quest, you will need to be at least level 78 to proceed to the next quest. After you reach level 78, talk to Alphinaud to accept the next quest: The Ladder.