Luna rides a battered old broom that keeps crashing itself into the school pond. She has a witch's hat and wand and sometimes she's quite good at magic, but she isn't completely sure that she's a real witch. She doesn't have a familiar for one thing, and she doesn't know where she came from - only that she was found by three witches who she now calls her aunts. When she swaps her moonstone ring for an Australian boobook owl in the Lost Forest, the mysterious bird seller makes her promise to keep the bird hidden for as long as she can. This is not easy when you live with very inquisitive aunts. And it's not easy when you find out that the fearsome Madame Valadon, the Best Witch in Paris, is missing her boobook owl and she's sure that Luna knows something about it. Could it be that Luna has Madame Valadon's boobook? Why then did the mysterious bird seller give it to Luna? Why did she say the bird belonged to her? A familiar can only belong to one witch, after all. Luna has lots of questions - the biggest one of all is who she really is.