Alice-Miranda has a birthday to celebrate and a village show to look forward to! Miss Grimm is allowing the girls to attend the annual Winchesterfield show for the first time. One of the highlights of the Winchesterfield show is the Queen's Cup horserace. But Aunty Gee's prize racehorse, Rockstar, is refusing to leave the stables. That is, until Alice-Miranda introduces him to her own naughty pony, Bonaparte. Preparations are coming along well until a series of thefts rock the community. Things quickly go from bad to worse when Alice-Miranda's beloved Bony is horse napped. Can Alice-Miranda uncover the culprit and get her horse back in time for Rockstar to compete in the race?