The Secret of the Old Mill (1927)

The Secret of the Old Mill is the third volume in the original Hardy Boys series of mystery books for children and teens published by Grosset & Dunlap. The book ranks 86th on Publishers Weekly's All-Time Bestselling Children's Book List for the United States, with 1,467,645 copies sold by 2001. This book is one of the "Original 10", some of the best examples of the Hardy Boys, and Stratemeyer Syndicate, writing.

This book was written by Leslie McFarlane in 1927 for the Stratemeyer Syndicate, who published it under the pseudonym Franklin W. Dixon. On January 1, 2023, the 1927 version entered into the US Public Domain, due to 2022 having been the book’s 95th year. However, the 1927 version is still under copyright in Canada until January 1, 2048, due to Canada using the author’s life plus 70 years model for works-for-hire. As Leslie McFarlane died in 1977, the last year for Canadian copyright on the 1927 version will be 2047. The 1962 version will enter the US Public Domain on January 1, 2058, and the Canadian Public Domain as late as January 1, 2067 (Alistair Hunter possibly died in 1996). Between 1959 and 1973 the first 38 volumes of this series were systematically revised as part of a project directed by Edward Stratemeyer's daughter Harriet Adams. In 1962, the original version of this book was rewritten in by Alistair Hunter, resulting in two different stories with the same title.

Plot summary (revised edition)

The Secret of the Old Mill

Frank and Joe Hardy and their friend Chet Morton wait at a train station in their hometown of Bayport for Frank and Joe’s father. While there, they see a man jump on a departing train. Frank is 18, and Joe is 17. Their father is a famous detective and is returning from a business trip to Detroit. When he doesn’t arrive, the brothers assume he has been unexpectedly delayed and plan to meet a later train. In the meantime, the three friends go into town to pick up Chet’s new microscope.

Ken Blake, a teenager who works as a bicycle errand boy, is almost hit by a car. Frank, Joe and Chet help him. Joe gives Ken an envelope he dropped, noticing it is labeled confidential and is addressed to Victor Peters. Ken thanks the boys but is vague about where he works. Frank inspects Ken’s bike, and Ken tells him it came from Belgium.

When Chet pays for the microscope, the shopkeeper tells the boys that one of Chet’s $20 bills is counterfeit. The police have warned local shopkeepers about a counterfeit ring. Frank asks the shopkeeper if he can take the bill to study it and then turn it over to the police. The shopkeeper agrees. The shopkeeper lets Chet take the microscope and owe the balance.

Chet asks to borrow $20 from his father, a real estate agent. He tells the boys about the property outside of town that he sold to Elekton Controls. The company manufactures missile parts, and the land purchased includes an old mill. At Chet’s father’s suggestion, the company renovated the mill. As the boys are getting out of Chet’s car back in downtown Bayport, they see the man from the train station but are unable to catch him. The boys pay the balance due on the microscope and go to the police station.

At the police station, the three friends learn that other townspeople have also received counterfeit bills. The man Chet saw matches the police description of one of the suspected counterfeiters. The boys go back to the train station, pick up Frank and Joe’s father and head home. Mr. Hardy doesn’t think the counterfeit case is related to his case, but he offers to help his sons track down clues. He also tells them that Elekton is doing experimental work, in addition to manufacturing.

In the middle of the night, Joe hears someone on a bicycle leaving an envelope in the Hardy mailbox. He chases the person without success. Awakened by the noise, the Hardy family, including Frank and Joe’s visiting Aunt Gertrude, reads the note and then searches the yard for clues. The note warns of danger for the family if the Hardys don’t drop the case — but it doesn’t specify which Hardy or what case. Aunt Gertrude finds a bicycle pedal outside.

The next morning Mr. Hardy, Frank and Joe examine the note in the lab above their garage, but they don’t find fingerprints or a watermark on the paper. After the boys are finished, Chet picks them up to follow up on the bicycle pedal clue. One of Bayport’s store owners identifies the pedal as a Belgian bike part and suggests they try a store in the neighboring town of Bridgeport. The Bridgeport store owner did sell that style of bike pedal, but could only give a general description of the customer.

Frank, Joe and Chet go back to Bayport for an afternoon outing with Chet’s sister Iola and their friend Callie Shaw. Chet plans to apply for a job at Elekton, and then the group intends to have a picnic and explore the area by the river.

Chet is unsuccessful at getting a summer job at Elekton. The guard at the gatehouse discourages Chet from applying without an appointment and gives the group the impression that there aren’t any openings. As the group starts to leave the plant, Frank notices a bicycle that looks like Ken’s leaning against the mill’s south wall. He still has the pedal in his pocket from their morning sleuthing, and it matches the other pedal.

The maintenance man confirms that Ken does work there, but indicates Ken isn’t there at the moment. As the group leaves the property, Joe thinks he sees Ken’s face in the window. Frank and Joe go back to talk the maintenance man. He still insists Ken is not there. Ken walks home at night, leaving his bicycle on company property, which makes it easily accessible to anyone. The boys begin to wonder if Ken purchased a new pedal in Bridgeport.