Hello, i think i know how. Make sure to save alot and i hope this helps you get past the quest. First, Get to learn about fawn. She can be found at the condo when you purchase a unit and go to sleep in it. Ask for her help in rescuing cassie after learning about her part time job. She will give a list on what needs to be done inorder to save her. Start leveling up your strength, and Began to find people to help you save her, Find lin lin at the happy massage, talk to her and pay her to take down the guards. Find sammy at the bath house and talk to her, she will give you a schedule about don's men. Fawn will also have a schedule. Search for Arlene at the police station, after meeting her and talk about dawn, go back to the slums and find the homeless people across from dons lair. A man will ask you to pay them 1000 for theyre help but go to sleep and come back the man will be gone, find him at the gentle men club and you will get half of it back. Give the rest to the homeless people back where you first payed them. Go back to arlene and that should be all, sorry for how long it is.