In "The Naughtiest Girl", Elizabeth Allen is sent to Whyteleafe School to become more disciplined and to learn how to behave. However, she has no interest in following the rules and immediately gets into trouble, often clashing with both her classmates and teachers. Her mischievous behavior, while entertaining, often lands her in difficult situations. As the story progresses, Elizabeth begins to realize the importance of kindness, responsibility, and teamwork. She learns that there is more to school life than just breaking rules and having fun — true friendship and respect for others are just as important.

The book highlights Elizabeth's journey as she grows from a rebellious girl into someone who learns the value of following rules, working with others, and being considerate. The story teaches valuable life lessons in a way that is both engaging and entertaining for children.