In the shadow of the palace in Yonghui's seventeenth year, a revenge about blood, power and swords slowly unfolded. In order to avenge the destruction of his family, the orphan of Xuanjiafang sneaked into the cleaning room, but in the bloody fog, he discovered that his younger brother Li Gouer had been refined into the "Blood Yin" of the blood butcher knife. At the same time, the cold palace maid Qingyuan appears with the secret treasure of the Iron-Blood Alliance. The two are involved in the royal conspiracy because of the fragments of the "Zhi Ge Sword" - Concubine Shu uses a civet cat in exchange for the prince to cover up the truth about her childlessness, while Supervisor Shang Fang uses the blood sacrifice of a child to forge an evil sword in an attempt to control the world in the name of the "Chosen Prince".
The collision between mechanism skills and sword-making skills runs throughout: the magnet gear of the puppet "Night Owl", the secret fire quenching of the Iron Blood Alliance's "Binding Immortal Silk", and the blood resonance of the Xuanwu Qisu Formation form a strange palace world. The birthmarks of the twins coincide with the star map, Qingyuan's blind eyes hide the power of breaking through illusions, and the fragments of the Iron Blood Order guarded by the Xian Fei in the cold palace all point to the "Stop the War" covenant between Xuanjiafang and the Iron Blood Alliance three hundred years ago. When the blank of the bloody butcher knife reveals the flesh and blood of his younger brother in the secret fire, and when the phantom of the Zhige Sword reappears in the resonance of the two bloods, under the light and shadow of the sword is not only a family feud, but also the ultimate question of "the sword is not wrong, but the fault lies with the person holding the sword."
The seven-day agreement of the heaven-sacrifice ceremony, the secret fire of dragon bones in the underground blood pool of thousands of people, and the poisonous schemes of the Shadow Guards are linked together, and the conspiracies are tightening like a spider web. Gu Ren and Qing Yuan wandered through machine traps and poisonous mist blood pools. They not only had to solve the blood puzzle of the "Ziwu Yuanyang Lock", but they also needed to protect the true royal blood in the whirlpool of intrigue. When the broken knife and the fragments of the Iron-Blooded Order are combined into the hilt of the sword of "black armor, iron-blood, and slaying evil spirits together", a life-and-death situation in which blood is the blade and fighting is the weapon,
