In this book, the final book, Felicity, Susan, June, Bonnie, Amy, Freddie, Lucy, Pam and etc are in their last term at Malory Towers as sixth formers. Gwendoline Mary Lacey is back as a teacher to teach the sixth form how to become a lady.
The new girl is Lizzie who moved up from the fifth due to being advanced at her studies. She has a sister, Edith, in the first form who becomes close friends with cheeky Daffy Hope (Sally's little sister). Lizzy does not like this and tries to spoil the fun for her sister. It is not a Malory Towers book without some spite. Someone is out to get Gwendoline and doing spiteful things to her.
Felicity Rivers becomes the head girl of the whole school, with Susan Blake alongside her as her deputy. June keeps her previous role of games captain of the whole school, and does a good job rallying up the youngsters.