[Travel through books + Qing palace + taboo monarchs and ministers + a mixture of pleasure and abuse] Shen Yan, a die-hard fan of modern Yongzheng, was electrocuted and transformed into "Xiao Yanzi", the eunuch of the Qing palace who poured night fragrance. It started off stinky, but he relied on sparring to avoid being beaten and scolded, and his drama shocked the emperor. He counterattacked from a low-level servant to become the "exclusive opera listener" of Yangxin Palace. He brought modern knowledge to solve the problem: document classification method to sort out the pile of memorials, chemical analysis to find out the source of poisonous fragrance, logistics thinking to solve the dilemma of water transportation; he used traditional skills to seek power: dramatization passed secret codes to catch the Queen's gang, scattered forces used force to break the Eight Master's conspiracy, and troupe makeup skills forged secret messages. While trying to protect Yong Zheng from the original plot of avoiding death by elixirs, and fighting against the plot correction power of "changing big things and leaving small details"; at the same time, he is sinking in the pull between "fans protecting idols" and "eunuchs loyal to the emperor" - Yong Zheng's domineering attitude when giving the ink jade finger ring, the tenderness of rubbing the bamboo bookmark late at night, and the determination of Shen Xingsi to rush in to save people, making this taboo and deep love across identities become more and more intense in the whirlpool of palace battles and previous dynasties. "Fourth Master, fate wants you to die, so I will change my fate against the will of heaven." "Yan'er, I want both the country and you." From being a slave to the night fragrance to being the confidant of the emperor, they fought against fate with their sincerity, and wrote a happy and sad legend of staying together within the red walls of the Forbidden City.