The first novel is set against the backdrop of political and military conflicts between the late Song Dynasty and Jurchens-led Jin Dynasty, while obscure Mongol tribes, united by Genghis Khan, emerge as a major world power. The second novel depicts the many military conflicts between the Song Dynasty and the Mongols. The historical Battle of Xiangyang is featured in the novel. The third and last novel is set in the Yuan Dynasty, established by the Mongols who eventually conquered the Song Dynasty and the rest of China. Towards the end of the third novel, the Yuan Dynasty is overthrown and the Ming Dynasty is founded.
The Book of Wumu is a fictional military treatise written by the Song Dynasty general Yue Fei. The book is highly sought after by the Jurchens of the Jin Empire, enemies of the Han Chinese-ruled Song Empire. Guo Jing uses the knowledge he acquired from the book to defend the Song Empire. Before his death, he hid the book in the blade of the Dragon Slaying Saber. Nearly a century after the Battle of Xiangyang, the book comes into Zhang Wuji's possession and Zhang uses one of the strategies detailed in the book to defeat the Ruyang Prince's forces at the siege of Mount Song. He passes the book to Xu Da later and Xu becomes a brilliant military leader after studying it. Xu leads the Ming Cult rebel forces to overthrow the Yuan Dynasty and becomes one of the founding pioneers of the Ming Dynasty.