Sign of the Four

The Sign of the Four is the second novel by Arthur Conan Doyle about master detective Sherlock Holmes and his partner Dr John Watson. In this story they solve a mystery of hidden treasure and murder.Miss Mary Morstan arrives at 221B, Baker Street to request help with the mystery of her missing father, her anonymous gifts of pearls and a letter requesting her to meet an unknown person that evening. Holmes takes on her case and the adventure begins.The story is set in 1888. The Sign of the Four has a complex plot involving service in India, the Indian Rebellion of 1857, a stolen treasure, and a secret pact among four convicts ('the Four' of the title) and two corrupt prison guards. It presents the detective's drug habit and humanizes him in a way that had not been done in the preceding novel, A Study in Scarlet (1887). It also introduces Doctor Watson's future wife, Mary Morstan.