This Sherlock Holmes short story concerns the theft of some secret papers relating to construction of a submarine, and the discovery of the papers in the pocket of the supposed thief, a young Government clerk, Arthur Cadogan West, whose body is found on an Underground line, apparently thrown or fallen from a moving train. Holmes exposes the real thief and killer, with the help not only of Watson, but also of his own brother Mycroft, who makes one of hsi rare appearances here. ( )