well, its about a vampire named Rain who runs away with her 3 friends and they like have to try to get out of the kingdom befor her father finds them and thats all i got so far... lol :)
You could write about Rain and her friend's adventures.Being attacked by other mythical creatures,if that's the direction you want to go,how they survive who they run into, and about them.Tell why they're running,her father could be a powerful man who thinks that she's a theart to her power and plans to eliminate her,her friends go cause that's the kind of people they are.Tell why she's a threat to his power,his's becoming king but he's a terrible one.People like her better and want her to have power.How she stops him.
Just an idea.Take what you want and if you get stuck again just ask.I'll help if this helped.
Good Luck~~!!