What's bonus for thunderhead keep?

I was wondering if anyone knew what the bonus was for this mission? I've heard lighting the 2 torch towers was the bonus but i've done that and doesn't seem to do anything. I've also wandered outside and saw that there were a bunch of dwarves doing nothing in a small village in front the of the fort you defend but it was guarded by a bunch of monsters in front and my team was yelling at me to get back and help so i stopped my search. So does that have anything to do with the bonus or am I just way off? If anyone knows what the bonus is I would much appreciate it. Thanks.

There's 3 bonfires to light, not two

Oh, that would be it then. Well where is the third one. The first 2 are easy to find, I know there is one right before you come into the fort but it doesn't seem you can light it, unless they fixed it so you can light it. If someone could tell me where the third one is I would most appreciate it.

Well, like I wondered before, where is the third one? Well there isn't, theres only 2. So after playing with henchman and wasting a good hour or so looking for the 3rd torch I figured I would play with a group and try lighting the only 2 torches and see if i get the bonus. Well guess what i did. I still don't know why. I've done it times before and didn't get the bonus. A couple of reasons may be they fixed it in the last patch. Also we lit the torches really quickly, i dashed to one side and another dashed to the other side and lit it as fast as possible after the scene. Or perhaps because we didn't allow the king to take one hit when he was standing up above in the fort. Or perhaps the bonus mission is just bugged. Who knows, I'm just glad I finally got it!