Tang Zuo collapsed, but the ashes were not yet cold. Zhu Wen usurped the Tang Dynasty and established the country, and the Central Plains entered the troubled times of the Five Dynasties with endless killings. The blood of Baimayi soaked through the land of Bianluo, etiquette collapsed, feudal towns were divided, officials were cruel, and wars continued for years. There are frequent omens in the world: ghosts appear in government offices in the middle of the night, dead soldiers scream at night in deserted camps, innocent souls in lonely graves seek their lives, and every strange and murderous case is attributed to ghosts and gods bringing disasters. But Netherworld has no sword, and what really kills people is the human heart and authority.
Shen Yanci, an orphan from Dali Temple in the former dynasty, managed to survive the massacre of his family in the Baimayi Incident. He hid in hiding in Liang Bianzhou incognito, and succumbed to the powerless prison warden. He inherited the Dali Temple's knowledge of investigating and breaking prisons, and was good at detecting corpses, breaking into secret rooms, and deducing conspiracies. He specialized in taking on those mysterious cases that the government did not dare to delve into and the powerful people deliberately covered up. He was determined to uncover the buried secrets behind the family members' deaths.
While wandering in troubled times, he met Su Qingyuan, a descendant of the Jiangnan medical clan. She travels the mountains and rivers carrying a medicine bag, is proficient in the toxicology of Qihuang, and can perform autopsies to identify traces. She is also familiar with the art of looking at the yin and yang, and can distinguish between real resentment and artificial illusions. She is used to being homeless and devastated, and feels compassion in her heart, but she is never afraid of the swordsmanship in troubled times.
One person is holding a prison book to investigate the case, and the other is carrying a medicine bag to solve the case. Two people with different backgrounds, tested and suspected each other from the first meeting, experienced life and death dangers, and entrusted each other in the cracks of dynasty changes. They traveled around the city walls of Bianzhou, the siege battlefields, the vassal towns and military villages, and the palaces and courtyards, peeling away layers of masks of ghosts and gods, and exposing the corruption, frame-ups, and treason hidden under the supernatural rumors one by one.
The so-called treacherous prison in the world is not in the Jiuyou underworld, but on the remaining land of the beacon fire.