Hardy Boys; Vol. 3; 11 oz.; 174 pages; HC no DJ Unread pencil priced inside light soiling outside edges light musty odor Hardy Boys #3 Matte Pictorial Cover. 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 their father is working on.