Plot summary

A long-distance telephone call from Chet Morton's uncle summons Frank and Joe Hardy and their staunch pal Chet to a summer art school, located near old Fort Senandaga which is reputed to be inhabited by a ghost. The young detectives' assignment: recover two famous oil paintings stolen from the valuable Prisoner-Painter collection owned by Jefferson Davenport. Mr. Davenport, millionaire sponsor of Millwood Art School, reveals that one of the famous Fort Senandaga pictures painted by his ancestor, General Jason Davenport, contains a clue to the hiding place of a priceless chain of gold.

Vicious threats and deadly traps beset Frank, Joe, and Chet as they search for clues to the stolen paintings and the gold treasure—a search that is complicated by a stormy feud between a proud Englishman and an equally proud Frenchman over the military history of the fort.

• Publication date: 1965
• Ghostwriter: David Grambs
• Summary: Chet asks the boys to help solve the theft of valuable paintings in New England, which leads to a hunt for a valuable gold chain in an eerie fort.