Mirabelle and Meg Moffat are twins and their mum and dad are famous circus acrobats. Mirabelle is fearless. She promises to be the most topsy-turvy, upside down acrobat of all. Meg does not. In fact, Meg is afraid of heights. Is Mirabelle afraid of anything? With her new grand show opening, Meg might be about to find out."--Provided by publisher.