This quest is not available in game.
Learn more about the cult's plans at the altar in the westerm part of Mirror Lake Orchard.
You're fitting in well here, <name>, but there is more to us than daily chores and spreading the message. I'm sure you heard a little bit about it when you first joined.
As you know, this world is ending and the unprepared will die painful deaths.
We have been given a gift, an opportunity to become something greater and more powerful. Overseer Talathor is preparing for a ritual at the altar just west of the orchard. Wait there for him, and learn more of your new brothers and sisters.