Sherlock Holmes and his biographer, Dr. Watson, are taken aback when a young lady arrives in their Baker Street rooms, demanding that Holmes should forthwith desist from writing her poison pen letters and harassing her in other ways. Holmes, naturally, denies the charge and convinces Elizabeth Penrose that he has no knowledge of the affair. To defend his good name, however, he feels impelled to look into the matter and his investigations lead to a tangled family trust which has prompted the current situation. Matters are confused by an American who is not quite what he seems, an old lady with definite views and a butler who chases Holmes, while Holmes in his turn is chasing a duplicate Holmes!
