While riding in their homemade iceboat on the frozen surface of Barmet Bay, Frank and Joe Hardy and Chet Morton discuss their plans for the upcoming Christmas holiday break. They visit Cabin Island but a mysterious stranger chases them off the island, The boys are invited to the home of Elroy Jefferson, a man whose car they returned in The Shore Road Mystery. They overhear an argument between Jefferson, the owner of Cabin Island, and Hanleigh, who is trying to buy the island. Mr. Jefferson rewards the boys and grants them permission to use the cabin for Christmas. After they arrive and their supplies disappear. Frank and Joe head to a village on the mainland to resupply and discover details about Jefferson, the cabin, the valuable Bender stamp collection and the servant, Sparewell. The boys eventually find their supplies on the island along with a Sparewell’s notebook with a cipher. They work to decode the cipher and discover the connection between Sparewell and Hanleigh. After some dangerous disasters, the Hardy boys solve the mystery of Cabin Island to the delight of Mr. Jefferson.

Much has changed in America since 1929. The modern reader may be delighted with the warmth and innocence of the characters; but uncomfortable with the racial, social, sexist terms and stereotypes. As such, this book is a part of our heritage, a window into our real past.