From the introduction:
Centuries ago, the city of Ikeda and its surroundings were terrorized by hosts of undead, until one day Shibato Masao united all the cities. The Masao bloodline seems to have an aptitude for controlling undead, so Shibato was able to drive away the worst of them. He was crowned emperor of the newly formed realm, and for generations, Shibato's heirs continued to protect it from renewed incursions of undead. Under the Masaos' reign, the empire and Ikeda, its capital, flourished.
This golden age has come to an end with the last few generations of monarchs paying little attention to the well-being of their people, focusing instead on gratification of their own desires. The current emperor, Kuno Masao, celebrates lavish feasts once a week, despite much of Ikeda's populace suffering from hunger. Kuno has sent out his tax collectors increasingly frequently, collecting money and food for his celebrations. Despite growing dissatisfaction, Ikeda's people have indulged Kuno so far, many hoping their contributions will gain them the emperor's favor, but the population is slowly realizing they have accepted things for too long. The situation is tense and violence is close to erupting.