Which episode is Zhang Jian's abandoned baby?

According to the plot of Seeking the Roots of the Imperial Capital, in the first episode, Jin Xiu's husband, Zhang, once went on a business trip with his colleagues and asked someone to predict where he could find his son, so Zhang and his colleagues went to that place and found his son. Huangchenggen is a TV series directed by and starring Wang. Broadcast on 1992.