This adventure serves to introduce the player characters to the midwestern wastes. All of them hail from Moserly, and times have been extremely tough. The KFS militia has been squeezing their tiny town harder and harder and with a recent drought, nearly all of the Brahmin in Moserly have had to go towards paying the tax. Food has become scarce as a result and to help their community survive, the players embarked on a hunting trip. If they can't eat their own Brahmin, they might as well stew some molerats or wolves.
The hunting trip itself isn't especially important for the GM. It is used as a device to get the characters out of town so that as they return the following encounters can continue. Any other reason would work, as long as the characters are return.
The characters approach their community after their hunting trip around dawn. Much to their surprise, they notice a column of smoke rising in the direction of Moserly. As they get even closer, they see that the entire town is in flames and that a group of raiders are nearly finished looting the place. No resistance can be seen and if the characters can get close enough, they'll realize everyone in town has been murdered by the invaders.
In fact, as soon as the characters get about a quarter mile from the town, a number of the raiders break off and start running in their direction.