A fairly solid Nancy Drew book, this one focuses on the circus. George is chosen to be Junior Ringmaster for the opening of the circus, but when she blows her special whistle nothing happens. The special whistle was switched with another one. They go through a list of suspects, but no one will admit to switching the whistles. Only when Nancy figures out that the "fake" whistle is actually a dog whistle does she piece together what happened. I was pleasantly surprised by the end. ( )