@Dcikmatized The man who committed in jail was the manager, who ruined the lives of many prostitutes. His death was the plan of Heesung just like the other murders. She is now planning to marry Ahn to gain even more power and money and to get rid of the pawns.
Officer Park once worked with manager Koo, but later started working for an anti prostitution thingy. He helped get Seong rok out of jail, and je oh helped him get a rise by finding a scapegoat for the murder, who committed suicide and the case was closed temporarily.
The new officer reopened the case that Kang once did, and he's trying to find out who actually killed the men from red light district.
President Cheon worked with Heesung and Ahn before, but decided to help the ex prostitutes and put the manager in jail, contacting officer Park to do so.
In short - president cheon ,Han Gyeol, Seong Rok and Je Oh are working together
Ahn, Heesung, Kim, the blonde man, possibly officer Park are working together
And Kang along with the new officer are trying to do the same thing, so they're working together as well
It's a bit messy, but i think this is all you need to know and I hope you got it now