In the bloody picture of rivers and lakes and intrigues, the orphan Gu Qingcheng is actually the leader of the dark palace "Lone Ying", who returns from the bloodshed with thousands of silk threads, just to find out the truth about the poisoning of her parents. Nan Fengwan, the legitimate son of the prime minister who appears to be a dandy, hides his identity as the commander of the Xuanyi Guards. He wields the Water-Breaking Sword to stir up trouble in the court, hoping to dismantle the Nether Sect that threatens the imperial power.
The two clashed several times due to the Menghun Poison Case and the secret treasure of the Tianji Tu. During the investigation, they gradually uncovered the shocking conspiracy of the twin bloodlines and the dragon veins of the previous dynasty. Gu Qingcheng disguised as a businesswoman and sneaked into Gu's house, only to discover that her stepmother Liu Ruyan was actually the left guardian of the Nether Sect; Nan Feng visited the gambling house at night, and the black lining on his sleeve revealed his identity. When the bone-corrosive poison attacks, Bai Zhi's "painful" antidote makes the two of them struggle between use and excitement.
The strategy of the Seventh Prince Xiao Jingyan's Hongmen Night Banquet and Ye Wuhen's Blood Ming Jue backfired, pushing the mystery of the twin brothers and sisters' life experiences and the struggle for imperial power to a climax. The intertwining of Qianjisi and Broken Water Sword is not only a life-and-death showdown, but also a game of ten years of blood feud and one-time heartache. When the secret map detonates the Dragon Vein Secret Room, the grievances and treachery of the court will eventually return to peace in the mist and rain in the south of the Yangtze River, and the pair of weapons sealed in the wooden box will eventually become a footnote to a legend about revenge and redemption.
