Deeply   bored by the lack of mental stimulus and the dull routine of existence,   Sherlock Holmes is about to resort to his daily dose of cocaine when an   elegantly dressed young woman called Mary Morstan enters his room and   presents her case to him and Watson. Following the mysterious disappearance   of her father ten years ago, and after answering, four years later, a   newspaper advert enquiring for her, she has begun to receive each year, on   the same date, a precious pearl in the post from an unknown benefactor. Now,   with the last pearl, she has also received a message, telling her she is “a   wronged woman” and asking for a meeting that very night outside the Lyceum   Theatre. Will the great detective accompany her and help her unravel the   mystery?
     
     First published in 1880, The Sign of the Four – the second Sherlock Holmes   novel after A Study in Scarlet, published three years earlier – will sweep   the readers away into a story of murders, betrayals, double-crossings and   stolen treasures, and is an enduring testament to the storytelling genius of   Arthur Conan Doyle.