Summary. Hercules Harrel ran away from home when he was 16 years old, and went to sea. On the last ship he served on, the dying captain gave him a book containing clues to a buried treasure in Kentucky. Hercules came to the area near the clubhouse to search for the treasure. He fell in with a gang of bad boys, who initially promised to help him search for the treasure, but eventually tricked him and stole the secrets of the book. The gang of bad boys was led by Hackbury. They had been stealing valuables from the area, and selling them to Squire Hornaby. Hawkins and Jeckerson bust the gang, capture Squire Hornaby and Hackbury, and find the treasure – an iron pot full of gold coins, hidden in the basement wall of the old mill on Banklick Creek. Hawkins gives the gold coins to Hercules Harrel.
The book ends in tragedy when Hackbury dies of sepsis, in a Watertown hospital, stemming from an infection of his injured foot. The death of Hackbury is indirectly due to Hawkins and Shadow Loomis. Hackbury had been using the old mill as a base from which to try to scare the F&S Club boys away from their summer camp on Banklick Creek. Shadow Loomis borrowed a bloodhound, and spread creosote in the old mill. Hackbury got creosote on his shoes, which allowed the bloodhound to track him easily. Hackbury figured out what was going on, and shed his shoes in order to shake the bloodhound. While fleeing barefoot through the woods, Hackbury injured his foot. His foot became infected, and in spite of Doc Waters placing him in a Watertown hospital and taking care of him, Hackbury died.