In this classic mystery, Sherlock Holmes and Dr. Watson are drawn into a complex case by the enigmatic Mary Morstan. Her father's disappearance ten years prior is linked to a vast treasure from India and a secret pact between four convicts known as 'The Four'. The investigation plunges them into a dark world of betrayal, murder, and a thrilling boat chase on the Thames as they hunt for a one-legged man and his deadly companion to uncover the truth behind the Agra treasure.