The play is adapted from the novel "The First Beauty in Chang'an" by Developed Tear Glands. In Yong'an, the capital of the country, Shen Wenqi, the official in charge of the construction, was convicted overnight and imprisoned because of the collapse of the West Canal in the city. When the nest is overturned, no egg is left intact. The two daughters of the Shen family, Shen Yi (played by Xia Nan) and Shen Zhen (played by Ouyang Nana), also fell into the quagmire one after another. In particular, the youngest daughter Shen Zhen has always been raised in the boudoir and is ignorant of the world. At this time, she is on the streets and can hardly protect herself. At this time, the court judge Lu Shiyan (played by Xu Zhengxi), who is in charge of investigating the case, is also confused because of his frequent dreams of various ties between himself and the mysterious woman. After verification, the mysterious woman who appeared in the dream was Shen Zhen, the daughter of the guilty minister. Lu Shiyan approached her step by step, and also walked towards his unknown destiny step by step. Around the case of the West Canal in the city, the two experienced life and death, entrusted trust, and fell deeply in love with each other. And Lu Shiyan also lived up to his trust and found out the truth of the case with the help of Shen Zhen. However, the real behind-the-scenes mastermind approached the two silently.