The Hidden Dragon in The Secrets of Three Kingdoms is in Bianyuan. Mrs. Bian said that killing Cao Ang was the first episode.

The thirtieth episode. According to the 365 classic website, the Hidden Dragon, the secret of the Three Kingdoms, told Mrs. Bian that killing Cao Ang was the thirtieth episode. Mrs. Bian's secret seems to be secret, but in fact there are traces to be found. Combined with history, it can be inferred that Mrs. Bian once planned a shocking murder, which is thought-provoking.