Realizing that several clues point to the involvement of people from Baredo, Frank and Joe and their friend Chet Morton fly down to Cayenne, French Guiana and then Baredo in the nearby Huellas to investigate.
But when the Hardy Boys and Chet Morton arrive at Captain Thomas Maguire's cabin on the edge of the hollow, he has disappeared.
Frank and Joe start by working undercover at Alden’s shop, while their friend Chet Morton takes an interest in jet propelling his bicycle, which leads to humorous results.
Chet Baker | Henry Morton Stanley | Chet Atkins | Morton Feldman | Morton | Samantha Morton | Morton Smith | Thomas Morton | Morton Subotnick | Morton's The Steakhouse | Morton Salt | Greenock Morton F.C. | Chet Huntley | Chet Culver | Thomas Morton (playwright) | Oliver P. Morton | Morton H. Smith | Morton Grove, Illinois | Marcus Morton | Levi P. Morton | Chet Morton | Chet Lemon | Chet Helms | Tex Morton | Morton Halperin | Morton Grove | Morton Glacier | Morton Deyo | Morton DaCosta | Morton Beiser |
A series of adventures begins for the Hardy Boys and their friends Chet and Biff after they are invited to spend Christmas vacation on Cabin Island at the invitation of its owner, Elroy Jefferson, as a reward for recovering Jefferson's car in The Shore Road Mystery.