A missing treasure. A secret pact. A case only Sherlock Holmes can solve. The Sign of the Four is one of Sir Arthur Conan Doyle's most gripping Sherlock Holmes novels, blending mystery, adventure, and brilliant deduction. When a young woman seeks Holmes's help to uncover the truth behind her father's disappearance, the investigation leads to a trail of hidden treasure, dangerous secrets, and a deadly pursuit across Victorian London. With the keen narration of Dr. Watson and Holmes at the height of his intellectual power, this classic novel delivers suspense, intrigue, and unforgettable twists that shaped the future of detective fiction. Experience a landmark Sherlock Holmes adventure—download The Sign of the Four today and immerse yourself in a timeless mystery.