Yun Lanyue, the legitimate daughter of a brocade weaving family, was summoned to the palace for her unique skill of "cutting clouds and embroidering the moon" to embroider the "Moon Pattern Robe" for the crown prince's enthronement. She secretly discovered that the cloud pattern on her brocade robe contained a poison that would kill the prince when exposed to the moonlight, and the design drawings were actually made by her master who had been missing for many years.
During the investigation, Yun Lanyue discovered the secret conversation between the master and the third prince - it turned out that the third prince coerced the master into making poison and wanted to use the brocade robe to kill his brother and seize the throne.
Just when she was about to secretly modify the robe to detoxify it, the master found her late at night and revealed the ultimate truth: the prince had deliberately asked the master to hide the poison. He had known about the third prince's ambitions for a long time and wanted to use the name of "assassination" to eliminate the gang members. The reason why Yun Lanyue embroidered the robe was because of her family's loyalty, so that she could become a witness of "the merit of protecting the Lord".
In the end, Yun Lanyue took advantage of the trick and embroidered a two-way mechanism into the brocade robe: it not only caused the poison to "accidentally" fail, but also left ironclad evidence that the third prince had coerced his master. At the enthronement ceremony, he exposed the conspiracy of the two factions in one fell swoop, protected himself and his family with brocade wisdom, and restored the court's order to clarity.
