From the introduction:
This adventure can be can be easily customized to a party of any size or level, or run as a level 5 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.
...
The border town of Edrath has long found itself the center of political tension between the neighboring kingdoms, despite not being a valuable strategic location. It's more likely to be razed in the event of war than conquered, an unsettling fate that a half-elf priest named Irann Blum believed was all too certain. In her desperation she beseeched the gods for help and was sent a glorious valkyrie to protect her town. However in time the valkyrie grew to despise the PC's neighboring kingdom and believed a holy war to purge the land of heathens is the only recourse. At least, that's what she tells adventurers.