This is a feature film inspired by the television series of the same name. Someone has stolen the musical score for the great Ferragosto concert composed by the Mapà; Pipì, Pupù and Rosmarina must take on the role of detectives in order to find it. They decide to stage three famous classical works, adapted to their own tastes, in three different theatres in the forest, hoping to lure the missing score out into the open. The first is L’Italiana in Algeri by Gioachino Rossini, followed by Jules Massenet’s Don Quichotte, and finally Pyotr Tchaikovsky’s The Nutcracker. It is the latter that seems to lead them toward the solution to the mystery, while their investigation is followed step by step by the ever-present voice of the narrator, who interacts with the three detectives.