The Sign of Four

A dense yellow miasma swirls in the streets of London as Sherlock Holmes and Dr Watson accompany a beautiful young woman to a sinister assignation. For Mary Marston has received several large pearls - one a year for the last six years - and now a mystery letter telling her she is a wronged woman.

Sir Arthur Conan Doyle (1859-1930) was born in Edinburgh where he qualified as a doctor, but it was his writing which brought him fame, with the creation of Sherlock Holmes, the first scientific detective. He was also a convert to spiritualism and a social reformer who used his investigative skills to prove the innocence of individuals.