Secret of the Old Mill

The third book in the classic mystery series "e;Hardy Boys"e; is titled 'The Secret of the Old Mill.' With almost two million copies sold, it comes in at number 86 on the "e;Publisher's Weekly"e; All-Time Bestselling Children's Book List for the United States. Ken Blake is saved from death in a bicycle accident by Frank and Joe. When the Hardy Boys give their friend Chet Morton change for what turns out to be a fake $20 bill, they discover that he was conned something the police subsequently verify is happening more frequently in their hometown of Bayport. Later, a clattering sound wakes Joe, and he sees an enigmatic person riding away from his house on a bicycle. A message bearing the words "e;Drop the case or else danger for you and your family"e; is discovered while looking into the disturbance. The Hardy boys are determined to find out who is threatening them even if they are unsure if it has anything to do with the counterfeiting case that Frank and Joe are looking into or another investigation that their dad, detective Fenton Hardy, is working on. Will they survive long enough to resolve both cases before danger gets to them?