Martin Clunes is excellent as the eponymous Arthur, sporting a genuine Scots accent and a Victorian gentleman's sensibility. Wonderful writing and period scenery provide a convincing platform for the actors to bring the plot to life. I have no knowledge of the historical reality of the plot but the device of having the real life characters of Sir Arthur Conan Doyle and his secretary as the protagonists in a crime drama provides an interest over and above the validity of the story or the sophistication of the plot. The writing is very well done, with the dialogue couched in antique terms and rhythms. The plot is subtly exposed over time through conversation, rather than the trite expositions of modern crime series. This can easily be enjoyed as a period piece or as an excellent crime drama.