The boys begin Part III of Season III with a bang, as they tackle Sir Arthur Conan Doyle's classic (but perhaps overlooked) Sherlock Holmes novel The Sign of Four. They discuss Holmes' method as a detective, especially compared to that of his rival Athelney Jones; the great sleuth's cultural blind spots; and whether emotion has any role in investigative work.   Theme music: "Shostakovich," by Mucca Pazza.