Enter the designated house. After the conversation, the wall on the left will move and you will be able to go down to the basement.. After another conversation, collect the flame thrower from the table and additionally, equip yourself with the rocket launcher that will come in handy later on. Exit the house to make a phone call, during which you will talk to Dennis.
Reach the first marked area. Expect that you will encounter enemy patrols on your way to your destination. Do not go to the foot and, instead keep to the right side of the crops . This will allow you to shoot at the barrels that will explode and kill guards as a result (try to lure them into that area by tossing stones), and will burn up the crops, if you are lucky.
When you are at the further crops, you should also remain on the hillock to the right. On every one of the crops that need to be burned up, there are barrels, so try and shoot at them whenever there are as many guards around them as possible. Every next field will be protected with more guards than the previous one so, be prepared to put up a fight with the pirates, or escape from their sight in order to lose them.
After you burn up five plantations, your next target is the boat in the fishermen's village. I recommend that you go into water and swim underwater, as close as you can, to the target.
As soon as you enter the pier, the boat will take its leave. Quickly, equip the rocket launcher, mentioned at the beginning of this mission, or the flame thrower, and destroy the boat. Now, jump back into water and dive to avoid fight with the guards on the shore. Swim away into safety and fast travel back to Badtown.