Adventure Title
Tribe/People/Folk of (the) Circle/Ring/Obelisk/Column

Alternate title
Priest/Priestess of the City

Opening Scene
An execution chamber that is Weird where they encounter Clergy that is/are Looking for new slaves

Plot hook and draw
An anonymous letter that is/has Sent a warning

Plot Concept
Gather information to prove the existence of something or someone that is motivated by Vengeance

Primary Antagonist
A guild leader who/that is Tortured

Plot fulfillment and location
A precious jewel from A pirate haven