In Enid Blyton's bestselling series, the Naughtiest Girl and her friends make their own rules at their very unusual boarding school.

In book nine, Elizabeth is furious when Kerry, new girl and young actress, becomes head girl over the obvious choice, her friend Emma. Elizabeth is convinced that all the seniors have been swayed by Kerry's acting skills.

How will Elizabeth prove that the real Kerry is a nasty piece of work without looking like the troublemaker herself?

Between 1940 and 1952, Enid Blyton wrote four novels about Naughtiest Girl, Elizabeth Allen. Books 5-10 are authorised sequels of the series written by Anne Digby in 1999.