In simplest terms, what do Jehovah's Witness believe in?

I hear about this religion a lot, but whenever I research it, I either get bias websites or a bunch of gibberish. Trying to not incorporate your prejudice's, what do they believe? What are they even (lack of better wording, I'm not meaning to be disrespectful)? Thank you... most insightful and respectful answer gets 10 pts. :)