The secret of the old mill
Franklin W Dixon (Author)
Determined to learn the secret of the old mill, Frank and Joe employ a clever ruse to gain entrance and become trapped. There they unravel two mysteries, one involving a counterfeiting case and the other a national security case about the missile parts that their father is working on
Print Book, English, 2016
Grosset & Dunlap, an imprint of Penguin Random House, New York, 2016