Dr. Watson pays a visit to Sherlock Holmes at 221B, but when the caring landlady Mrs. Hudson tells him that she has neither seen nor heard from her lodger for a whole week, Watson begins to feel that his dearest companion might be in some trouble and resolves to undertake an investigation in the style of Sherlock Holmes which will disclose disturbing crimes halfway between past and present and prove that the former army surgeon is not at all the stupid friend of the gifted detective.