Frank and Joe Hardy, erstwhile teenage detectives, feel somewhat foolish after accepting a counterfeit bill while helping a stranger at the Bayport train station. Over a period of weeks, friends and family members fall prey to exchanges with counterfeiters, sometimes in transactions amounting to hundreds of dollars.
Frank and Joe’s father, the highly esteemed private detective Fenton Hardy, is working with the Secret Service to track down the counterfeiting ring, but thus far they haven’t had much luck. It’s up to Joe and Frank, piecing together their suspicions, to locate the secret printing plant of the counterfeiters and bring them to justice.
