As the story opens, Holmes, with the aid of a microscope, identifies minute blobs of glue on a cap found beside a murdered policeman at St. Pancras station, a clue that strongly implicates a picture-frame maker who has denied the cap is his.

Holmes was at the forefront of his profession in using forensic science this way. A pioneer in the use of trace evidence such as shoe prints, minute marks and scratches, and traces of blood, mud, organic matter, and other particles such as glue, Holmes’s technique emphasized the minute study of a crime scene to yield tiny clues. This method is now the centerpiece of modern forensic investigation.

It is no coincidence that the great real-life visionary of forensic science, Dr. Edmond Locard (1877–1966), came to be known as the “Sherlock Holmes of France.” Locard’s cardinal rule was that “every contact leaves a trace.” Known as “Locard’s exchange principle,” this simple statement—which might have been made by Holmes himself—argues that every criminal brings something to a crime scene, and takes something away—however miniscule.

Dr. Edmond Locard (1877–1966) was a pioneering French scientist who established the first police laboratory in 1910, although its work was not officially recognized until 1912.

Shortly after Holmes correctly identifies the blobs of glue, he receives a visit from John Mason, the head trainer at Shoscombe Old Place, a grand country estate in Berkshire. Mason is worried about the behavior of his master, the rakish Sir Robert Norberton. A notorious spendthrift, Sir Robert is in a deep financial hole. To clear his debts, he is relying on his prize racehorse, Shoscombe Prince, to win the prestigious upcoming Epsom Derby at falsely long odds (he has cleverly misled watching touts with the horse’s much slower half-brother on morning gallops).

Mason is concerned about other recent events, however. Why have Sir Robert and his reclusive and invalid sister—to whom he has always been devoted—suddenly stopped meeting? Why has Sir Robert given away her beloved pet spaniel to the landlord of a local inn, the Green Dragon? Why does Sir Robert meet a mysterious person in the haunted family crypt under the old ruined chapel late at night? Where did the mummy’s head and bones that Mason and Sir Robert’s butler, Stephens, found in the crypt come from? And finally, why was there a charred fragment of human leg bone among the ashes from the central-heating furnace in the cellar under Lady Beatrice’s room?

The Derby Day (1856–1858) by William Powell Frith depicts a scene Sir Robert would have been familiar with. The work was so popular that the Royal Academy added a rail to control crowds.

With that last grim question, Holmes is hooked. Have Sir Robert and an as yet unidentified accomplice murdered Lady Beatrice and burned her body? Pretending to be vacationing fishermen, Holmes and Watson check in to the Green Dragon inn, where the landlord, Josiah Barnes, warns them about Sir Robert. “He’s the sort who strikes first and speaks afterwards,” he says. Undeterred, they offer to take the landlord’s spaniel, once owned by Lady Beatrice, for a walk, and head straight for Shoscombe Old Place, timing their arrival to coincide with her daily coach excursion. As the coach slows down by the gate of the estate, Holmes releases the dog. It dashes towards the coach enthusiastically, then suddenly starts barking furiously at its occupants—supposedly Lady Beatrice and her maid, Mrs. Norlett. But from behind “Lady Beatrice’s” shawls, Watson and Holmes hear a harsh man’s voice shouting, “Drive on! Drive on!.” As Holmes observes, “We have added one card to our hand, Watson, but it needs careful playing, all the same.”

Later that evening, the pair visit the crypt. The bones Mason saw are gone; Holmes speculates they have been burned in the furnace, along with the rest of the skeleton. Just as he discovers a recently opened coffin, the pair hear footsteps, and “a terrible figure, huge in stature and fierce in manner” appears from the shadows. It is Sir Robert, and he demands to know who they are and what they are doing there.

In a wonderfully Gothic moment, Holmes flings open the coffin, and Sir Robert reels back and cries out. The body of Lady Beatrice is revealed, “swathed in a sheet from head to foot, with dreadful, witch-like features, all nose and chin, projecting at one end, the dim glazed eyes staring from a discoloured and crumbling face.” Sir Robert resolves to explain his actions, and invites Holmes and Watson to accompany him to the house for an explanation so that they can judge the matter for themselves.

He tells them that, about a week earlier, Lady Beatrice had died of dropsy. As a result, he faced losing the house, the stables, and all the horses—including Shoscombe Prince—just weeks before the hoped-for Derby win that would pay off all his debts, because the entire Shoscombe estate, including the racehorse, was actually hers, and would therefore revert to her late husband’s brother when her death was known. In desperation, Sir Robert had decided to conceal her death until the race had been run.

To make room for her body in the old coffin, he and his servant, Mr. Norlett, the maid’s husband, first had to remove the mummified body of an ancestor, and burn it in the furnace. “There was no indignity or irreverence,” he claims. He then explains that Norlett—“a small, rat-faced man with a disagreeably furtive face,” and once an actor—agreed to impersonate Lady Beatrice. They gave away her spaniel because it kept yapping at the old well-house where they initially hid her body.

When Holmes calls his conduct “inexcusable,” Sir Robert retorts, “It is easy to preach. Perhaps you would have felt differently if you had been in my position.” Holmes—a man who on previous occasions has let killers walk free when he felt their actions were justified—is clearly not persuaded, and declares it a matter for the police. In Watson’s words, the Shoscombe Old Place case ends “upon a happier note than Sir Robert’s actions deserved.” Given that the crime turns out to be so minor, the police take a lenient view and largely overlook it, simply rapping Sir Robert on the knuckles for failing to register the death of his sister immediately. Also, remarkably, Sir Robert’s creditors agree to wait until after the race to be paid. And finally, Sir Robert’s horse, Shoscombe Prince, wins the Derby, netting his owner £80,000 in bets, which allows Sir Robert to clear all of his debts and set himself up for life.

As Holmes discovers, the reality of Sir Robert’s life at Shoscombe Old Place is very different from how it first appears. The master of a large estate and owner of a prize-winning racehorse, he is, in fact, in grave danger of losing everything.

Watson’s description of the events in the crypt is unusually dramatic, reading like something from a horror story. He describes the appalling sight of Lady Beatrice’s corpse, and the terrifying figure of the giant Sir Robert, in such Gothic detail that we are led to believe something appalling is going to happen. Instead, minutes later they are all sitting comfortably as Sir Robert tells a mundane story about a delay in reporting the death of an old invalid.

In “Shoscombe Old Place,” Holmes uncovers not some terrible murder or dark cruelty, but instead a foolish and highly distasteful fraud perpetrated by a desperate, slightly unpleasant landowner—a fraud that the man in question also gets away with. It is something of an anticlimactic end to Holmes’s career, and perhaps this is just what Conan Doyle intended. Watson begins the story with the remark, “He is one of those men who have overshot their true generation,” and refers at the finish of the tale to “a career which has now outlived its shadows and promises to end in an honoured old age.” In each instance he is talking about Sir Robert, but the descriptions could equally well apply to Holmes himself.