Inside the revolutionaries' headquarters, you will find a map of the castle and the surrounding town.  Also, you will find a long list of grievances against the King, both by his subjects and the Queen herself.  In addition, there are crates full of weapons and armor, as well as a small vial of poison.
hidden revolutionaries' headquarters, Inside Palace
duke
queen
I need a new cushion for this throne! All this chatter in court is giving me a headache!  That Lord that just walked past offended my nose with his odor.  I need to find my chambermaid.
Oh! this throne is killing me! It won't just be the throne, ma'am, if these grievances hold any substance. I'm worried for your safety. I had enough of this books! I need to get some fresh air and see the sun! The words within these books may be our only saving grace, ma'am. Perhaps if words are not your weapon, we arm ourselves more obviously? There is an army's worth of armor and swords in here. Duke, teach me how to use this sword... You're the head of the revolutionaries, ma'am. There's no need for modesty, your skills are renowned. Where on this map will our first assault take place? I think we need to use this poison. It is the easiest way although not the one that I want to do. The king trusts you like his own. Will you take the risk? If the poison is detected, there is going to be an uprising. The whole headquarters will be exposed. They have found a very unique way of detecting poisons in their food. They use dogs, ma'am. Very radical but they have been very effective and a set back for us. Perhaps there is something within this pouch? This... this is a very rare herb, duke... I think if we make a poison from this her, this could be our answer! Perhaps the dogs won't have encountered this! It still comes with a risk though. Can we be this impulsive? Perhaps some ball play whilst we ponder on the matter? I'll put it in this pouch and please bring to the alchemist. Tell him this is from me and he will know what to do. I will prepare some men outside the castle to prepare for attack. We'll put this poison in their food and weakened the army as well As you wish, ma'am. 