In Kitty at St. Clare's, the story centers around Kitty, a new girl at the school. At first, she struggles to fit in and find her place among the established students, especially with the dominant personalities of other girls at St. Clare's. However, as Kitty spends more time at the school, she starts to grow and learns important lessons about friendship, kindness, and how to cope with her own feelings.

Kitty is initially quite different from many of the other girls at St. Clare's, and she faces some difficulties as she adjusts to the school's strict rules and social dynamics. However, as the story progresses, Kitty’s character develops, and she begins to make her mark by showing bravery, fairness, and determination.

Throughout the book, readers will find the usual mixture of school adventures, minor pranks, and moral lessons that Blyton is famous for. Kitty’s journey toward becoming a well-rounded and more confident individual is a key theme in this book, and it serves as a reminder of the importance of personal growth and staying true to oneself.