Hardy Boys 07: the Secret of the Caves

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 a new clue is unearthed that sends the young detectives to the Honeycomb Caves. After many dangerous encounters  Frank and Joe discover a powerful searchlight in one of the craggy caverns along the seacoast. In the brilliant white glare of the searchlight the startling secret of the caves is dramatically revealed.