In the third year of Yongxi's reign, the celestial phenomena changed, and rumors of the emergence of the "Nine Heavenly Secrets" set off the world. In order to cure the cold poison, Cang Minghai's orphan Yun Suwang disguised himself as a wandering doctor and sneaked into the Central Plains. However, he was involved in a bizarre murder case: all the members of the famous martial arts family "Qingyun Village" suddenly died overnight, and the corpses were all covered with frost. It was suspected that Cangming's martial arts school had committed the crime. In order to prove his innocence, Yun Suwang was forced to cooperate with the court's chief detective and embark on the road to pursue the murderer.
On the way, he met Chi Yan, who believed that "the sword is the truth", and Su Xin, who could understand yin and yang, and the three of them investigated together. They discovered that behind the murder was a restoration conspiracy of the "Liluo Sect", a bereaved family of the previous dynasty, and that the key clue "Nine Heavens Secrets" contained "Yanyang Jade" that could cure Yunsu Wanghan's poison...
From the yellow sand in the north of the Great Wall to the misty rain in the south of the Yangtze River, from the mysterious array of the underground palace to the secret realm of the snow-capped mountains, Yun Suwang gradually uncovered the truth behind the destruction of his family - he was actually the "key" to the secret. When his best friends and loved ones swing between interests and beliefs, he must make a choice between heaven and humanity: to become the guardian of the secret, or the vengeful god who devours the spiritual veins of heaven and earth?
