From the introduction:
This adventure can be can be easily customized to a party of any size or level or run as a level 8 adventure for 5 players. It can work as a small side adventure in an existing campaign, as a standalone one-shot, or the start of a new adventure. Use the links to the tools in their relevant section to customize the adventure to your party.
Barrheller is a defensible-looking city with imposing walls and an alert garrison, and has been the site of many battles. Positioned within a desirable mining spot near the edge of 3 borders, it has frequently changed rulers throughout history. The halfling kingdom of Zelterry conquered the city 5 years ago during the previous war and now stand as the rulers. The rich mines have usually made this a prosperous city, but signs posted warn citizens to stay away from the mines, and the city looks like it has fallen on hard times.