Abnormal Ever After

Everyone knows the classic fairytales such as Cinderella, Snow White, etc. They all start with "Once upon a time" and end with "lived happily ever after". We know these stories from beginning to end, however, what happens when a fairytale book ends up in the hands of three young laddies but the stories are not exactly the classic ones you grew up on. Even worse, these unfamiliar stories don't all have endings as the pages to some of the stories run blank.
With no ending to certain stories, what are they to do with the book? Maybe they will just have to finish the stories and come up with the ending themselves.