The fourteenth book in the Hardy Boys series, originally published in 1935. In this book, the Hardy Boys head South to settle a feud. Franklin W. Dixon is the pen name used by a variety of different authors (Leslie McFarlane, a Canadian author, being the first) who wrote The Hardy Boys novels for the Stratemeyer Syndicate (now owned by Simon & Schuster). This pseudonym was also used for the Ted Scott Flying Stories series.
It all starts when Fenton Hardy, is engaged by an experimental race car and motor designer to investigate a series of mysterious accidents. Three of his drivers have crashed because the windshields of their cars were suddenly crazed, thus cutting off forward vision. Frank and Joe uncover one slim clue. Each of the drivers had seen a signpost marked 'Danger' shortly before the accident.
When the Hardy Boys eagerly agree to assist their friend Jack Dodd and his father in locating a family treasure, the two young detectives are unaware of the baffling complications that will arise.
Triggered by the disappearance of a brilliant young professor, this mystery takes the Hardy boys first to Kenworthy College, where they find a puzzling message on an examination paper. But then their pal Chet Morton, with his new metal detector, and buddy Biff Hooper, turn up a clue that sends the young detectives on an exciting search in another direction to the honeycomb caves, on the seacoast. A hot tempered hermit who considers the caves his private domain complicates this seacoast mystery and challenges every sleuthing skill Frank and Joe possess.
The Hardy boys are elated over their good luck when wealthy Elroy Jefferson invites them to spend Christmas vacation at his private retreat on Cabin Island. But when Frank and Joe make a reconnaissance trip in their iceboat to the island, a belligerent stranger orders them off. Why? Before twenty-four hours have passed, the Hardys find themselves involved in two mysteries: the first concerns the recent disappearance of Mr. Jefferson's grandson, Johnny; the second, the baffling theft of a priceless collection of antique medals which took place two years ago.
