The story takes place in the middle of the fictional Dayin Dynasty (corresponding to the transitional style between the Tang and Song Dynasties in real history, integrating the feudal separatism of the Five Dynasties and Ten Kingdoms and the prototype of the civil service system of the Song Dynasty). It has been more than a hundred years since the founding of the country and has gone through seven emperors. The current one is Emperor Yinxuan Zhao Heng. On the surface, the dynasty showed a "resurgence" - commerce and trade in the Gyeonggi region was prosperous, the imperial examination system was perfected, and water transportation to the south of the Yangtze River was smooth; in fact, internal and external troubles were intertwined: the "Beihan tribe" (nomads, powerful horsemen and archers) in the north would invade the border every autumn and plunder the Sixteen Prefectures of Youyun; in the south, The "Minyue vassal town" (the first vassal king was a descendant of the founding hero and inherited from generation to generation) relied on its own troops, controlled the salt and iron monopoly, and only paid 30% of taxes; the court was divided into the "Wenzhi faction" (led by Prime Minister Liu Chengye, who advocated disarmament, peace talks with Beihan, and weakening the vassal town) and The two factions of the "Wuxun Sect" (led by Qin Lie, the privy envoy, advocated preparing for war, regaining Youyun, and cutting down vassals by force) fought overtly and covertly, while Emperor Xuan tried to balance the two factions in an attempt to stabilize the imperial power.
