From the publisher:
Nina is a girl in middle school with a little brother and a single mom who barely has enough time to spend with her. Put down at school by nasty cliques, Nina's life is not much fun. All this changes when a magical fairy named Sybil turns up in Nina's backpack! Sybil and Nina have a blast giving Nina's tormentors a taste of their own medicine. Theres only one problem: demons from the magical world that Sybil comes from have followed her to our dimension, and theyre out to cause some damage of their own!