The Sign of the Four is the thrilling follow-up to Sir Arthur Conan Doyle's premiere novel, A Study in Scarlet in which he introduced the world's first unofficial consulting detective, the legendary and brilliant Sherlock Holmes.

In this tale, young Mary Morstan seeks out Holmes' assistance in unraveling a strange mystery: ten years earlier, her father - a Captain in the army - went missing after arriving back in London after a long overseas posting. Four years after her father's disappearance, Mary receives a gift via post: a large and valuable pearl, a bequest that would be repeated annually for six years. The last pearl, however, arrived with an invitation for Mary to meet with her mysterious benefactor, claiming that Mary had somehow been "wronged," prompting Mary to seek Holmes' advice. Holmes takes the case and embarks on an adventure involving hidden treasure, betrayal, revenge...and a miniature, poison-dart shooting assassin! (This is also the story wherein Dr. Watson, Holmes' faithful companion, falls in love with Ms. Morstan and they agree to marry, much to Holmes' chagrin.)

The Sign of the Four is one of the most revered and exciting tales in the Holmes canon and is presented here in its original and unabridged format.