What Makes A Good Bedtime Story?

So, I'm trying to make-up a bedtime story for this contest I'm in, but I don't know what makes a good bedtime story. I have this so far: Long Live. Yeah, it's not very good, and if I'm not careful it'll turn into a full-length novel. It has to be short, but it's hard to write an epic bedtime story that's short. I'm trying to make it Magic Tree house length, maybe shorter, but definitely not Harry Potter length.

I only have 2 weeks left until it has to be turned in, so I may have to shorten it, but I want it to be the best bedtime story in the contest. Any of you have any suggestions to what makes a good bedtime story?
May 20th, 2012 at 11:40pm