The Sign of Four

Since her father vanished, Mary Marston has received a perfect large pearl - one a year for the last six years - and now a mystery letter telling her she is a wronged woman. Sherlock uncovers a tale of treachery and human greed that ranges from penal settlements on the Andaman Islands to the opium-fuelled violence of Agra Fort during the Indian mutiny.

The Sherlock Holmes series is a collection of short stories written by Arthur Conan Doyle. It is now rewritten in easily accessible, clear, modern English.