Publisher's blurb:
In Stairway to Hell, the characters visit Summer Fort, a sprawling city with an out-of-the-ordinary problem. A third of the population is affected by a strange affliction of the mind that causes them to become aggressive, impatient, and danger-seeking. This has revived the gladiatorial industry and caused all kinds of trouble as people kill each other in the streets. A perilous faction broke into the palace last week and gravely injured the queen.
The few clues lead the party to a ruined keep where the seers of Ord claim evil gathers. The characters investigate the place and find a hidden compound underneath. An arcane artifact lies there, an obsidian stairway that can be used to summon demonic entities from hell. A wizard has been using it to bring forth Tragmuth, the Puppet-master. This demon is responsible for the strange behaviors of Summer Fort's population. The characters must put a stop to this plot.