Dr. Thorneycroft Huxtable (what a name!) is the founder and principal of a prep school in Northern England known only as Priory School. He calls upon Sherlock Holmes to return with him to Mackleton regarding the disappearance of a student, 10-year-old Lord Saltire, son of the Duke of Holdernesse. As with the boy, the German master Heidegger has also disappeared, along with his bicycle.
Upon meeting Holmes, the Duke reveals that he believes his estranged wife has nothing to do with his son’s disappearance, nor has there been a ransom demand of any kind. Holmes believes the nearby road could not be used without being seen. The police seem to confirm this with the discovery of the boy’s school cap in the possessions of some gypsies (author’s term, not mine). They plead innocence, saying they found the cap on the moor, but the police arrest them all the same.
Holmes and Watson find a bicycle track, but it does not match Heidegger’s tires. In observation, one tire has a patch on it. All other evidence has been destroyed by rampant cow tracks. The tracks from Heidegger’s bicycle is found, ending where they find his body. Our duo make their way to the Fighting Cock Inn, and the innkeeper, Hayes, seems surprised that they should want to go to nearby Holdernesse Hall with news of the Duke’s son. During lunch, Holmes realizes there are a lot of cow tracks, but no cows. The hoof prints suggest uncowlike behavior — galloping, trotting, cantering, and so forth. They sneak into the innkeeper’s stable and discover the horses have been recently shod with old shoes and new nails. When investigating the nearby smithy, the innkeeper forcefully demands they leave.
James Wilder cycles down the road from the direction of Holdernesse Hall, looking agitated. He arrives at the inn, and it isn’t long before a trap pulls out of the stable yard on the road to Chesterfield. Later, under the growing darkness, another visitor arrives at the inn. Wilder’s bicycle tires are noted to be the same as the first ones encountered on the moor.
At Holdernesse Hall the next morning, the Duke is under the weather. Even so, Holmes demands to see him and likewise demands from him the promised reward for the information regarding the boy and his kidnappers. Holmes reveals that the young lord is at the inn, and he accuses the Duke, stating that the mastermind of the affair is James Wilder, the Duke’s illegitimate son. The plot was designed to force the Duke to change his will. The police would not be called, of course, as scandal must be avoided at all costs. The weak link was Hayes, whom Wilder hired to do the kidnapping. The innkeeper fled, but has since been caught on Holmes’ information. It was he who killed Heidegger. Wilder confessed to the Duke upon learning this, and the Duke arranged for the innkeeper to escape justice and let to let his younger son stay for another three days to cover up the affair.
Hayes is sentenced to death by hanging, the young lord is brought home, and the Duke writes to his estranged wife, looking for reconciliation. The source of their estrangement, Wilder, is heading to Australia to seek his fortune.
The cow tracks were a special effect of sorts, made by shoeing horses with shoes shaped like cow hooves. Just a personal note… I really want to see what those shoes would look like and to know whether or not such things would potentially cripple a horse. I’m probably not supposed to ask questions like that. Aside from this one tiny little point of order, this is one of the more forensically-intensive stories in the canon so far. It certainly reads better than I’ve described it here, but really… what story doesn’t? The real highlight of the story, as far as I’m concerned, is watching Holmes eviscerate the secretive machinations of the noble class. Conan Doyle takes a lot of pride in knocking the upper class down a peg or two, calling them out on the foibles that acknowledge them as being anything but superior. His delight translates pretty well into the story.