This mission begins where the last one left off, so head inside the building to confront the man in white. Once the initial conversation is over, a secret area opens up, so go downstairs for another cutscene. Willis is his name and he wants you to burn some drug fields, and a boat, that belong to Hoyt.
Leave the building and Jason will call Dennis to tell him what has happened, which Dennis promptly tells Jason to avoid Hoyt since he is even worse than Vaas. Since the drug fields should be in uncharted territory, your first goal should be to head to the Radio Tower that is southwest of the drug fields.
Once you're finished with the Radio Tower, head to the drug fields. When you're get near it, use your camera to locate two guys sitting in the middle of the field. Approach from behind them and use a Chained Takedown on them (if you have it). Note that when you get inside the radius of the fields, you will automatically equip the Flamethrower (you can switch weapons).
When the coast is clear, all you have to do is catch a little bit of the crops on fire and it will spread to the rest. Also, there are explosive barrels you can use to spark some flames. Once the two fields are burnt up here, you will need to move on and burn some more. You will notice that Jason's vision is getting blurry, which is some side effects of the drugs burning.
The next area is crawling with enemies, so you will need to be extra careful. Use your camera to tag as many enemies as possible and if you have a ranged weapon, use it to shoot the barrels from as far away as possible. You need to burn 5 more fields, 3 of which are up top and there will be 2 more below. Once all of the crops are nice and toasty, you will need to head to the fishing village.
As you approach the fishing village, you will run into some more enemies. As always, scout the area before charging in, as it will likely lead to your death. If you can, distract guards to secluded areas and perform a Takedown on them. There might be one Heavy (shield icon) in the area, which will be your biggest problem, so if you have any explosives, use those. Once you get close to the boat, it will take off, so grab the RPG-7 from the crate and fire it, hitting the boat and finishing the mission.