On the surface level, it seems that this movie simply tells the story of a procuress who was on her way bring back the runaway singing girl, being killed by a hatchet man, the one (boatman) who was involved in trafficking women for the upper class, after she saw through his tricks.
In fact, what is implying in this movie is that the procuress shared the same fate as the singing girl. When she was at her age, she was also forced to be parted from her son, who she left a jade pendant to, hoping that she might recognize him in days to come. However, it turned out at last that the boatman was her lost son.