When English teacher Gemma Lamb's school flat is wrecked by storms, maverick headmistress Hairnet insists the girls must fund its repair by setting up their own businesses - the start of a series of hilarious unintended consequences. Meanwhile Gemma's worries are compounded by the arrival of bossy new girl Frieda Ehrlich, sponsored by a mysterious local tycoon whose wealth is of dubious origins. Fearful for the school's reputation, Gemma recruits an old friend to help investigate the tycoon's credentials, jeopardising her romance with sports teacher Joe Spryke. What is Frieda hiding? Why is her sponsor living in a derelict manor house? Why is his chauffeur such a crazed driver? And what has become of McPhee, Hairnet's precious black cat? With a little help from her friends, Gemma is determined to solve these mysteries, restore her flat and save the school.