You are to check with the other Scions about traveling together back to Castrum Oriens.
This quest is available if you have completed the quest Token of Faith, and have reached level 61.
Starting the Quest
Talk to Alphinaud in Rhalgr's Reach to begin the quest.
Speak with Y'shtola
Use the nearby Aethernet Shard to go to the Western Rhalgr's Reach Aethernet Shard, then go northwest to where the orange arrow is pointing in the minimap. Talk to Y'shtola and there will be a cutscene.
Speak with Alphinaud
Go southwest to where the orange arrow is pointing in the minimap. Talk to Alphinaud to proceed.
Speak with Raubahn at Castrum Oriens
You can either teleport to Castrum Oriens, or you can go south to exit Rhalgr's Reach, then go west to where the orange arrow is pointing in the minimap. Talk to Raubahn and there will be a cutscene.
Speak with Alisaie
Talk to Alisaie to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to Pipin to accept the next quest: In Crimson It Began.