In the summer of 1889, a young Londoner and consultant hydraulic engineer, Victor Hatherley, recounts the strange events that occurred to him the night before, initially to Dr. Watson and later to Sherlock Holmes.

Hatherley was visited by a man who identified himself as Colonel Lysander Stark and offered a confidential 50 guinea (£52.50, equivalent to £6,173 in 2021[1]) commission to examine a hydraulic press at a country house in Eyford, Berkshire that Stark claimed was used to compress fuller's earth into bricks. Despite his misgivings and theorising that Stark was lying about the machine's true purpose, Hatherley felt compelled to accept the offer, as his business was newly established and he had little work.

Upon arriving at an appointed train station, Hatherley was picked up by a carriage with frosted glass windows and traveled what he believed was a considerable distance to the house. Distracted by his desire to be paid, Hatherley ignored a woman's warnings to escape before he examined the press and made recommendations on how to fix it. Upon further investigation however, he discovered the floor was covered in a "crust of metallic deposit." Realising his theory was right, he confronted Stark, who then tried to kill him with the press. After the woman helped Hatherley escape, a murderous Stark pursued him with a cleaver, forcing Hatherley to jump from a second-storey window, losing his thumb to Stark in the process. Surviving the fall and landing within some rose bushes, Hatherley passed out and later awoke by a hedge near the train station.