Superintendent Gréco and Inspector Max Beretta are drawn into a sulphurous place, a magnificent castle transformed into an ultra-select nightclub, where Madame Maude brings together for the pleasure of her wealthy clients young students who are not shy. . But the French secret services have already taken over the premises for a secret operation, and Greco's team will have no choice but to investigate incognito. Rose, always there and ready to help, disguises herself as a call-girl while Beretta takes on that of a client, which causes many misunderstandings...