Hardy Boys 7 - 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 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.