This audiobook is narrated by an AI Voice. *The Adventure of the Engineer’s Thumb* is a tense, fast-paced Sherlock Holmes thriller filled with shadowy criminals, deadly traps and narrow escapes, narrated by Dr. Watson.

Shortly after Watson establishes his own medical practice, a distraught young hydraulic engineer named Victor Hatherley arrives at his door, grievously injured—his right thumb has been brutally hacked away. Hatherley recounts an extraordinary midnight assignment: a mysterious, gaunt man calling himself Colonel Lysander Stark offers him fifty guineas to travel to a remote Berkshire house to repair a faulty hydraulic press, demanding absolute secrecy.

Persuaded by the generous fee, Hatherley takes the late train to Eyford. He is driven deep into the countryside to an isolated residence, where a frightened woman urgently begs him to flee. Ignoring her warning, Hatherley inspects the machine and quickly realises the story about fuller’s earth is a complete lie. The press is built for counterfeiting coins. When his discovery is uncovered, Stark locks him inside the chamber and activates the machine, intending to crush him to death.

Hatherley narrowly escapes through a hidden panel, aided by the mysterious woman. As he climbs out of a second-floor window to flee, Stark strikes him with a cleaver, severing his thumb. After waking alone beside a roadside hedge with no house in sight, he makes his painful way to Watson, who brings him to Sherlock Holmes.

Holmes pieces together the counterfeiting gang’s scheme. The group moved Hatherley while he lay unconscious to hide their location. Holmes, Watson and Scotland Yard race to confront the criminals, only to find the house engulfed in flames. The gang has fled, destroying evidence of their illegal operation. Though Hatherley loses his thumb and promised payment, he survives one of the most perilous adventures Watson ever recorded.