It's a kind of complicated storyline to explain, so visit Wiki!
I actually was just starting to try to explain the basics of the plot myself, but I deleted it. I always waffle on for ages when explaining storylines while other people can cover it all in a few sentences, because I always include every little detail. Oh well, Wiki can do it for me! But if you ever get to watch it, do, because it's pretty cool.
I'm off to watch American Idol, because my dad is in control of the remote and he has no taste in tv programmes.