After witnessing a horrific public execution in the name of the Eternal Fire you can go to Triss’s house. There you will find two looters and can decide to fight them or not. It doesn’t matter much if you do but no matter what you do you can ask them about what’s going on. Captain Menge interrupts and takes the men away allowing Geralt to speak with him briefly.
GAMER TIP: Search Triss’s house with Witcher senses and loot the bookshelves. Some of the books can be used to update your Bestiary with info about Vampires and in Triss’s bedroom you’ll find a Rose of Remembrance which you can ask Triss about later if you collect it.
Once you re-enter the area where the witch and doppler were executed you’ll see a cutscene and be given two options to finding the King of Beggars hideout.
1. Speak with Beggars
When the cutscene is over approach the beggar on the left sitting on top of a scaffolding. Be nice, and do not mention your true intentions for talking to him right away and he will tell you where to go and what the password is.
2. Follow Thieves
This one is a little more involved. IF you follow the wrong thief than you will be ambushed, follow the right one and he will lead you straight to the hideout. If you lose track of him you can still speak to a beggar.
HIDEOUT PASSWORD: “The old sow’s farrowed piglets”
Here you will be able to reunite with Triss and help her with a job she has, which is getting rid of mice in a local mill. There you’ll have a brief conversation and she’ll ask about Yen. You’re response here doesn’t affect any future chances of romance with her.
GAMER TIP: You’re going to be ambushed after clearing the mill of rats so negotiate to get paid in advance to get some extra money.
After this quest is completed Triss will give you a lead that opens up the next main quest Novigrad Dreaming.