Publisher's Synopsis
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 and buddy Biff Hooper turn up a clue that sends the young detectives in another direction-to the Honeycomb Caves.
After many dangerous encounters, Frank and Joe discover a powerful searchlight on one of the craggy caverns along the seacoast. In the white glare of the searchlight, the startling secret of the caves is dramatically revealed.
