"The Sign of the Four" is a detective novel by Arthur Conan Doyle that features the iconic character Sherlock Holmes and his friend Dr. John Watson. The story begins when Mary Morstan, a young woman, seeks Holmes's assistance in uncovering the truth behind her father's mysterious disappearance and the subsequent arrival of a valuable pearl. Her case leads them into a complex web of theft, betrayal, and a hidden treasure linked to a pact among four individuals. The novel emphasizes themes of justice and morality, as well as the intricacies of human relationships.
The investigation takes Holmes and Watson on an adventurous journey across London, revealing the darker side of the city and its criminal underbelly. As they unravel the mystery, they discover that the treasure is connected to the Indian Rebellion of 1857, which deepens the stakes of their pursuit. The characters they encounter, including the enigmatic Thaddeus Sholto, add layers to the narrative and highlight the various motivations that drive individuals to crime and deception.