What a tricky scenario! At first you have to release a small detachment of imprisoned crossbowmen, confronted with lions to deal with ... then establish a decent food provision by eliminating those pesky hostile archers who steadily are targeting your peasants on their way to work. Luckily enabled to buy the demanded weapons as crossbows or leather arms, it's about to keep your population happy as well in order to get gold for different trading measures in view of the successful completion of all quests; and how to compile these 100 stones? Actually, I don't give any hints at that point ...