You have safely reached Kholusia, and Szem Djenmai has information that may help you find Alphinaud.
This quest is available if you have completed the quest In Search of Alphinaud.
Starting the Quest
Talk to Szem Djenmai in Kholusia to begin the quest. You can reach Kholusia by speaking to the Aspiring Amaro Tamer at the Amaro Launch in the Crystarium.
Deliver the Lake Thyme to Eybor
As you proceed, you can use the Aether Compass to find Aether Currents. For more information, read How to Unlock Flying.
Go southwest to where the orange arrow is pointing in the minimap. Talk to Eybor to hand over the Lake Thyme.
Wait for Alphinaud
Go north to where the orange arrow is pointing in the minimap. Attune to the Stilltide Aetheryte, then enter the northeast building. Check on the sparkling Destination. Answer Theva's question however you wish.
Search the Field for Vermin
Go outside and go north to where the orange arrow is pointing in the minimap. Go to the southeastern part of the orange circle on the map and go through the gate in the fence there, then go to the southwest part of the orange circle and check on the Blighted Crop. Kill the Pestilent Swarm that attacks. Then go northeast and check on the Blighted Crop and kill the two Pestilent Swarms that attack.
Knock on the Barred Door
Go south until the open gate is to your left, and go through the gate. Check on the sparkling Barred Door.
Knock on the Barred Door Again
Check on the sparkling Barred Door.
Knock on the Barred Door A Third Time
Check on the sparkling Barred Door. There will be a cutscene.
Speak with Theva
Go south to where the orange arrow is pointing in the minimap. Enter the northeast building and talk to Theva to complete the quest. There will be a cutscene.
Next Main Scenario Quest
After you complete the quest, talk to Alphinaud to accept the next quest: Open Arms, Closed Gate.