As an orphan, Maggie Fishbone is sent to the notorious Midwatch Institute for unwanted girls, and she expects the worst. However, Maggie quickly discovers that Midwatch is different from what it seems – it is a secret training ground for aspiring female detectives! The eccentric headmistress, Miss Mandelay, warmly welcomes the outcast girls and encourages them to explore their talents and learn all sorts of useful skills – such as how to escape from a crocodile or speak Swiss German. Soon, Maggie and her new friends embark on a dangerous adventure in the sparkling city full of secrets, leading them deep underground and high above the clouds… Will they solve the case of the missing Miss Fenchurch? An exciting mystery for all fans of Enola Holmes – with exceptionally useful tips for future female detectives.