Series: Finishing School #4
Sophronia is older here, now one of the more senior students, but she's still investigating a possible Picklemen plot (honestly that whole secret society with a pickle theme is just odd) and gets into lots of trouble. There was also a fun segment near the beginning of the book where the girls were tasked with acting like another girl as an exercise and thus confusing the other people they're interacting with.
Overall I'd say that this series was a light and amusing read, despite the general air of danger, and the audio was a good option. Because Sophronia is a student investigating what could be characterized as a crime (basically it is but it's not clear how without giving out spoilers), I'll be counting this one for the "Baker Street Irregulars" square for Halloween Bingo.