From the introduction: The world is ravaged by nuclear bombs or something, water is irradiated beyond anything you can drink, and beer is the primary source of hydration. Settlements are built around bars with micro-breweries attached to them, and the best paying jobs require skilled drivers to carry kegs from one town to another in a sort of beer-cultural-exchange program. As one might imagine, robbery is commonplace in a lawless nuclear wasteland, and trying to get the beer from town to town is dangerous business.