The Secret of the Old Mill

"The Secret of the Old Mill," the third book in the Hardy Boys series by Franklin W. Dixon, follows Frank and Joe Hardy as they investigate a mysterious counterfeiting operation in their hometown of Bayport. When they receive a strange, counterfeit bill at the local post office, the brothers suspect that something sinister is afoot. Their sleuthing leads them to an old, abandoned mill on the outskirts of town, where they uncover evidence of a secret criminal operation. As they dig deeper, Frank and Joe face various dangers, including booby traps and threats from the criminals involved. Using their wit, courage, and the help of their friends, the Hardy boys work to expose the counterfeiting ring and bring the culprits to justice. "The Secret of the Old Mill" is a gripping tale of mystery and adventure that highlights the Hardy boys' detective skills and determination.