Haechi Season 1 Episode 20

Saheonbu threatens to resign all its members unless the right to investigate the murder case involving Prince Yeoning is given to them. The king calls Prince Yeoning and asks him to tell him everything he knows about the recent incidents. When he does, the king is deeply moved and decides to give Prince Yeoning three days to prove himself innocent. The investigation of the murders leads to human trafficking deals with Qing and to the courtesan house.