Here is a simpler and less prosaic perspective to you:
A spoiled young girl must enter as a slave worker in a bath/massage club to repay their parents debt. She must work hard doing difficult and dirt chores while trying to find a way out. He cleans the body of a client plagued from a nasty contamination, and as reward receives a small gift that could help her to be free.
Meanwhile, she treats nicely a shy client and allow him in the building. The client soon gets obsessed with the girl and starts spending a lot of gold to pass more and more time with her.
Yep, is a film for children.
When the rich weirdo realizes is being blocked and distracted by the greedy staff, he has a tantrum, turns in a violent monster and starts destroying the place and eating alive anybody that stands in the path to her.
The girl flees, but finally decides to return to help him, the monster is appeased, they travel together and the character is finally rehabilitated far away from the bathhouse.
After a last chore, finally the girl befriends the madamme and is allowed to go and quit the bathhouse in good terms, see their parents again and keep with their former life. She is ordered to never tell anybody, never look back and forget all about the sordid place. Happy end.
Moral of the history: the solution to child abuse is hide it, never tell to anybody and pretend that nothing happened.
