1: Merchant’s camp area
2: Guards who ask to see pass
3: Barracks with 20 buccaneers
4: Densely packed animal pen
5: Guard tower with 4 buccaneers
6: Seedy-looking man selling passes to see the captain
7: Slave pen
8: Two guards watching slave pen
While passing by the slave pen, you may encounter a young boy with a heart-shaped birthmark on his shoulder and a fat merchant who is talking about buying him. You are presented with the option of saying nothing, punching the merchant, agreeing, or rescuing the boy. Punching the merchant will bring his guards, but they are easy to defeat. The disturbance will bring the camp’s captain, but he will just give you a warning about causing any more trouble. Saying nothing or agreeing will not do anything. Rescuing the boy, however, will. You can either sneak into the pen or attack the guards - trying to sneak into the pen will not work.
To accomplish the mission in the most direct, quick way, buy a pass to see the captain and talk to him about buying the young boy. He will sell him to you, though at a high price (the exact price is never mentioned). You can then easily leave the compound and return to the city. To avoid having to pay the buccaneer captain’s price, try releasing the penned-up animals to create a distraction while you break into the slave pen and grab the boy. Fleeing the compound will be easy in all the commotion. You will get stopped just before the gate, but it is a very easy battle.
On the other hand, if you want to cause the largest amount of mayhem and destruction, you can try taking out the captain first. You can either buy a pass to see the captain (doesn’t really cost anything) or just attack his guards directly. For buccaneers, they are unusually resistant to bribing. If you overcome them, you will find they have chain mail +1 and longswords +1. But several (three, to be exact) waves of more guards will appear after they are beaten. They are mostly 0-level buccaneers, but there are a few 3rd- and 4th-level fighters mixed in - they usually have longswords +1 and chain mail +1, so make sure you have some Detect Magic spells memorized to use. Finally the captain of the camp will step forth and challenge you to battle. This is where Hold Person will come in very handy. The captain is a bad-ass and you will have trouble taking him out without using magic. Once he has been defeated, make sure to grab his plate mail +3, shield +2, and longsword +4. Then the fort will be yours and you can come and go as you please.