Mystery of Cabin Island # 8
The Hardy Boys by Franklin W Dixon
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'scar in The Shore Road Mystery. While they are collecting the keys to the cabin from Mr. Jefferson they meet Mr. Hanleigh who is interested in purchasing the island. As well, Mr. Jefferson asks the Hardy boys to locate his grandson Johnny who has gone missing.