The Mayor of Illmarsh asked you to investigate The Recondite Order of the Indomitable Sea in connection with strange disappearances and bizarre occurrences in Illmarsh. He promised to reward you with information about The Dark Rider.
You discovered that The Recondite Order of the Indomitable Sea is not an order dedicated to Gozreh. It is actually a cult of Dagon.
You discovered The Vizier of the Recondite Order was headed to The House of Undiomede to try and meet with The Neighbors down the Bay, to “foster” a young couple’s daughter.
The Vizier seems to have been attacked by a mysterious slug creature. The same kind of creature nearly infested Mordren. These creatures seem to explode their victims head. The Cult had collected the bodies of many missing persons, victims of the slugs.
You discovered that a visiting Merchant from Caliphas, and victim of the strange slugs, was actually an agent of the Whispering Way. He coordinated a trade off between The Dark Rider and whoever holds the unnamed artifact the Whispering Way needs. This meeting was to take place at The House of Undiomede.
Hidden behind the Altarpiece in the Temple of Dagon is a small wooden door with a brass nameplate over top of it. It is clearly many years old. The nameplate reads: “Walter B. Derleth”