Tataru relays a message from Alphinaud that your presence is requested at the meeting of the Allied leaders in Ul'dah.
Requirements
This quest is available if you have completed the quest Volunteer Dragonslayers.
Starting the Quest
Talk to Tataru in Revenant's Toll in Mor Dhona to begin the quest.
Speak with Alphinaud
Go to Ul'dah and go to the Chamber of Rule Aethernet Shard, then go south to where the orange arrow is pointing in the minimap. Talk to Alphinaud. There will be a cutscene.
Speak with Alphinaud Again
After the cutscene, talk to Alphinaud to proceed. There will be a cutscene.
Speak with Marcelain
Go to the Coerthas Central Highlands. You can teleport to Camp Dragonhead to get there. Then go to the quest icon on the map and talk to Marcelain.
Defeat the Dravanian Forces at Whitebrim
Go west to where the orange arrow is pointing in the minimap. Dismount and enter the purple circle. An Assault Wyvern and three Horde Runners will attack. Defeat them, and two Assault Wyverns will attack. Defeat them to proceed.
Defeat the Dravanian Forces at Providence Point
Go east to where the orange arrow is pointing in the minimap. Dismount and enter the purple circle. Three Horde Scouts will attack. Defeat them, and two more Horde Scouts will attack. Defeat them, and a Horde Commander will attack.
Report to Marcelain
Go southwest to where the orange arrow is pointing in the minimap and talk to Marcelain to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to Marcelain to accept the next quest: The Steps of Faith. There will be a cutscene.