You have alerted the Gnath and all that remains is to await capture.
This quest is available if you have completed the quest Breaking into Hives.
Starting the Quest
Talk to Ysayle in the Dravanian Forelands to begin the quest. There will be a cutscene.
Enter the Inner Chamber
If you need to leave and come back later, use the Sacrificial Chamber Exit behind you. You can then use the Sacrificial Chamber Entrance west of the Gnath hive to re-enter the chamber.
In the Sacrificial Chamber, go south through the gate to the orange circle on the map. 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.
Thok ast Thok (Hard)
Use the Duty Finder to enter Thok ast Thok (Hard). Please see the Thok ast Thok (Hard) Guide for a walkthrough.
After you complete the duty in Thok ast Thok and exit the area, there will be a cutscene.
Speak with Ysayle
Talk to Ysayle to proceed.
Speak with Alphinaud
Go north to where the orange arrow is pointing in the minimap. Talk to Alphinaud 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: Mourn in Passing.