Three years have passed since Sherlock Holmes and his nemesis Moriarty vanished into the abyss of the Reichenbach falls. In that time the criminals of London have been able to sleep safe in their beds. But with the appearance of a dangerous individual with an air gun, the capital has never been in greater need of its protector. And so it is that Dr Watson meets a mysterious deformed man who reveals the truth behind the fateful final conflict between Holmes and Moriarty, and paves the way for the extraordinary return of the world's greatest sleuth in thirteen new tales of mystery and deduction.

Sign of the Four

by Arthur Conan Doyle

Published 1 February 1890
Since her father disappeared ten years ago, Mary has received annually and anonymously a pearl. When she is finally requested to meet the sender she is accompanied by Holmes and Watson. The stranger relates to them a tale of secrecy, hidden treasure and sudden death.