After you have completed either In Cervisia Veritas or The Butcher of Cidaris (or both, if you are especially ambitious) return to Dethmold with your findings on the rebellion. Speak with him, and he will send you four soldiers as backup. This is not necessary, but it will help you during an upcoming battle. After you have received your reinforcements, head over to the brothel. You can find the brothel outside of the borders of the main camp. You will have to head out through the right-hand entrance, which will put you out by the wilds of the Pontar Valley. From here, head out through the walls and to the left. Keep heading left to find a small bridge. Cross over the bridge to find an extension of the camp, where the brothel is housed.
Approach the brothel and you will find yourself faced with a prostitute named Madam Carole. Show her the square fish coins that you received during your last quests, and she will be reassured. Ask her to speak with a girl named Whistling Wendy. She will go fetch the girl for you. When she inquires, tell Whistling Wendy the following password: “I want your smile to part the gates of paradise.” She will understand that this is actually the rebel password, and she will let you in. Follow Whistling Wendy to the secret entrance to the hideout of the rebels. Drop down the shaft to enter the cellars beneath a large tower. The first door you come to will house a rebel named Vinson Traut. He is the head of the conspirators. Ask him for the chainmail armor, which you will need for the Courage Symbolized quest, but he will refuse you. He will know of your allegiance to Dethmold, and he will call you out on it. You will have several dialogue choices at this point, but none of them will matter. No matter what you say, your choices will lead you into a battle against Traut.
Boss Battle: Vinson Traut
You should be accompanied by four soldiers right now thanks to Dethmold. This will make the battle against Traut a lot easier than it would be otherwise. You will be in a pretty small arena for this battle, made all the more cramped by the presence of the four soldiers. As long as you have these soldiers at your side, you really don’t need to worry about tactics for this battle. Simply cast Quen on yourself to shield yourself from incoming damage for the next several seconds, and wade into battle. Attack Traut even as your allies move in for the kill. Launch an all out assault against him, using a combination of quick and heavy strikes to keep him off balance. Your allies should help to this end, as well. With a little help, you should be able to fell Traut in no time.
Without allies, this battle becomes significantly tougher. It will no longer be feasible to simply cast Quen on yourself and wail on Traut as much as possible. Instead, you should hang back and focus on tactics and traps. Use Yrden to set traps across the floor of the small arena. At some point in the battle, Traut is practically guaranteed to step into one of the traps. Use this opportunity to run up and attack him mercilessly until he frees himself. Repeat this process one or two more times to bring Traut down for the count. Whenever he gets too close, block his attacks and try to dodge roll away. From your new position, you can set more traps and cast Quen if necessary.
After you have defeated Traut, you should loot his corpse. You can find Seltkirk’s Armor on his body, which you will need for the Courage Symbolized quest. You can also find A Hog Named Henselt, a poem of sorts that was written by none other than Dandelion condemning the King. Finally, you will find a key on Traut’s body. This key will open the exit to the cellars, so take it and proceed out of the area.
When you get back to camp, head over to the left side, across from the cantina, to find Dandelion. Talk with him about his incendiary texts. Dandelion will refuse to back down. He will say that through his art he can express himself however he wishes. He will also say that he supports Henselt’s removal from power, and he will claim that Henselt is allied with Nilfgaard. This will basically end the conversation, so head out and find Dethmold again. He will reward you for your actions and hand you 300 orens. You can refuse the pay and tell Dethmold that he wouldn’t understand your motives, but you had might as well just take the money. It could prove useful later.
This will end the Conspiracy Theory quest for now, but it won’t be over for good. You will be returning to this quest at the very end of Act 2. For now, though, feel free to proceed onto more pressing matters.