Yeah, this campaign will not be easy street. I think a month ago, I started- but didn't finish- a detective story. What I did was pretty good, just it wouldn't be a good campaign opener. I will really need help with a story for this campaign.
If more suggestions lead towards the revenge idea, I have some ideas for that too... the only problem is having the idea of just killing one man into a campaign- unless you have a Kill Billish list of people you want to kill, and some would have body guards. Or it could be a general of some country invades the island you are on (rogue or not, I don't know). They don't send too many heavy weapons because the island has hardly a fighting force. The general kills the President of the island to make a point he is in charge. Your character could be his body guard, his wife, or something like that. You are going to kill the man that did it. You would be doing it strictly for revenge, not to liberate the island. You would go places, kill troops to tell the general you mean business and to get info (there should be a reason he can't leave). And so on.
If you even have a better idea then my ideas above, just tell me.
ALSO: just because I wrote more on the revenge idea doesn't mean it is the way I like better, it is just I have more ideas for it.