Pipin investigated the waterways where you lost contact with the Scions and has news to share.
This quest is available if you have completed the quest An Engineering Enterprise.
Starting the Quest
Talk to Tataru in the Forgotten Knight in Ishgard to begin the quest.
Speak with Pipin
Go to Ul'dah and use an Aethernet Shard to go to the Ul'dah Aetheryte Plaza if you are not already there. Go southeast up the stairs, then go east to the quest icon on the map and talk to Pipin. 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
Use an Aethernet Shard or the main Ul'dah Aetheryte to go to Central Thanalan via the Gate of Nald. Then go northwest to where the orange arrow is pointing in the minimap. Talk to Urianger to proceed. There will be a cutscene.
Speak with Alphinaud
Go to Gridania and use the Aetheryte or an Aethernet Shard to go to the Conjurers' Guild Aethernet Shard. Talk to Alphinaud to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to Alphinaud to accept the next quest: Lost in the Lifestream.