Where's the Weasley?

Ginny writes stories for her young children, nieces and nephews. This year its Hugo Weasley's turn to receive a book, if Aunt Ginny and Uncle Harry make it in time for his birthday party. What will the story be about? *Follows on, kind of, from 'Dont tell Mum the Babysitter's Dead', but you don't have to read that one to understand this. Rating is for the end.