The Last King of Scotland

So, I have this movie at my house from netflix. The name of it is The Last King of Scotland.
I have no idea what it is about, even though I have seen the previews in the theater. So, based on the cover of the book, I will assume the movie is about its title. I will now tell you what I think it is all about.

There is this dude. He is black. Forrest Whitaker plays him. Well, he has a fancy uniform that he uses for parades. One day he realizes that there are not any kings, not even Britain, which is run by a queen. So since he is already the ruler of Scotland, which I think is in Ireland, and also very close to Britain, he decides to be the King. Well this other dude comes along, he is played by James McAvoy. I am guessing that he is a history student or something, because he really knows about royalty and stuff and he has a really huge problem with Forrest becoming the king. Oddly enough Forrest likes him anyway and he lets him move into this castle. One of the things that Forrest can do, at least based on the book cover, is smile really big and shoot a gun out of his finger. His big smile makes you think he is nice and then he finger bangs you to death. This is how he plans to take over Scotland, Ireland. Finger-banging all the important people to death so he can take over. Well James stops him. I am not really sure how, but I am guessing there is a lot of yelling, there is probably at least one woman in the movie, she will probably cry about something and the dude will have to pretend to care to get her to stop. I think Forrest will die and since being a history major, without a gun-finger, a smile, a snazzy uniform, or parades, James will not be able to take over and he will have to become a teacher.

I will let you guys know how close I was to the plot I think is real, after I watch the movie.