Claudine at St. Clare's is the sixth and final book in the original St. Clare's series, focusing on the highly spirited and rebellious French girl, Claudine, who arrives at the school. Claudine's unconventional nature and her habit of speaking her mind cause significant disruptions and conflicts. The O'Sullivan twins and their friends must learn to understand and tame Claudine’s wild behavior. The book is an examination of cultural differences and the challenge of integrating a difficult personality into the tight-knit school community.