You have found a suitable gift for Y'shtola, and after a word of explanation from Urianger, you head for the gate.
Requirements
This quest is available if you have completed the quest A Little Faith.
Starting the Quest
Talk to Urianger in Lakeland (underground) to begin the quest.
Speak with Myrcant
Go northeast and go up the stairs to go outside. Then go northeast to where the orange arrow is pointing in the minimap. Talk to Myrcant to proceed. There will be a cutscene.
Speak with Urianger
Go east to where the orange arrow is pointing in the minimap. Check on the sparkling Destination and 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 Y'shtola
Talk to Y'shtola to proceed.
Speak with Y'shtola Again
Go northeast to where the orange arrow is pointing in the minimap. Talk to Y'shtola to proceed.
Speak with Y'shtola Once More
Go east to the quest icon on the map. Attune to the Aetheryte if you wish, and talk to Y'shtola to complete the quest. There will be a cutscene.
Next Main Scenario Quest
After you complete the quest, talk to Y'shtola to accept the next quest: A Day in the Neighborhood.