The Secret of the Old Mill

In "The Secret of the Old Mill," the third installment of the Hardy Boys series by Franklin W. Dixon, brothers Frank and Joe Hardy delve into a perplexing counterfeiting operation in their hometown of Bayport. Their investigation begins with a suspicious counterfeit bill received at the local post office, leading them to an abandoned mill where they encounter both evidence of criminal activity and various dangers. Armed with their detective skills and teamwork, the Hardy boys navigate challenges as they seek to uncover the truth and bring those responsible to justice.