From the introduction:
Descent into Darkness is an add-on adventure for The Moonbridge Raid Part 3: Anamos Isle to the Liberated Land.
This adventure will take place soon after the LightRaiders enter Anamos Isle.
This scenario is intended to provide an interlude adventure that takes place during The Moonbridge Raid Part 3: Anamos Isle to the Liberated Land.
The scenario is distributed as a text file with two JPG map files and one JPG image file.