I don't think this contest is really a 'fanfic' contest. You can write original fiction too where you can make up characters. I think she meant write a short story and the theme of it will be 'rebirth'. Seeing as it's an abstract theme, you can look at it from many different angles and get many different results. It doesn't really have to mean 'dying' and being 'reborn' literally. Am I making any sense?