The Adventure of the Engineer's Thumb

Early one Morning, engineer Victor Hatherley arrives at Watson's practice missing a thumb. The Digit was lost, he say, not by accident, but during a murderous attack which he barley escaped alive. Unable to say where it happened, he cannot lead police to his attacker. Watson encourages Hatherley to recount the whole thrilling adventure to Holmes, certain that Holmes will deduce the location and see justice prevail.