The Hardy boys search for their father when he disappers while investigating a house that is either haunted or a hide-out for criminals.

Once again Frank and Joe Hardy accept the challenge of a puzzling case when their famous detective father asks the boys to assist him in tracking down a notorious jewel thief and his accomplices. The trail leads to the outskirts of the Hardys' home town and to a weirdly guarded mansion on the old Perth estate. With their chubby, ever-hungry friend Chet Morton, Frank and Joe tackle another mystery -- one which has baffled the town of Bayport for many...

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...