Aymeric is planning a ceremony in Ishgard that he wishes you to attend, and you head to Ishgard to learn the details.
Requirements
This quest is available if you have completed the quest The Word of the Mother.
Starting the Quest
Talk to Alphinaud in Matoya's Cave in the Dravanian Hinterlands to begin the quest.
Speak with Aymeric
Go to Ishgard and use the main Aetheryte or an Aethernet Shard to go to the Forgotten Knight Aethernet Shard. Go east through the doors behind Firmalbert. Talk to the Temple Knight Guard and say Yes to proceed. There will be a cutscene.
Speak with Lucia
Go outside and use the Aethernet Shard to go to the Skysteel Manufactory Aethernet Shard. Go northwest to the small stairway, then go clockwise around the Skysteel Manufactory building. Go through the barred gate and continue northwest to reach the Coerthas Western Highlands.
Go to the quest icon on the map and talk to Lucia to complete the quest. There will be a cutscene.
Next Main Scenario Quest
After you complete the quest, talk to Lucia to accept the next quest: Staunch Conviction.