Valuable diamonds are missing, and the thumb-print of one Reuben Hornby is discovered in some blood at the bottom of the safe from where they were taken. An open and shut case, surely. Or is it? For reasons known only to himself, Doctor John Thorndyke has some doubts about the evidence. But to prove the innocence of a young man he must make his case in open court through the use of the latest Edwardian science. Will Dr. Thorndyke succeed, or will the case of the red thumb mark prove to be not only his first case, but also his last?This all-time classic has been given a new lease of life through Steve White's thrilling new production. Expertly narrated, this audiobook is perfect for existing fans of the good doctor and newcomers alike.