: One of the students, the son of the Duke, disappears from the boarding school. Sherlock Holmes discovers a boy abducted by his older illegitimate brother.
Mr. Huckstable, Master of Arts and Ph.D., is contacting Sherlock Holmes for help finding the missing son of the Duke of Holderness. The great detective is very busy, but he is ready to get down to business, especially since the duke gives five thousand pounds to the boy’s whereabouts, and a thousand if the abductors are named.
Mr. Huxtable is the director of the boarding school for boys, the best and most privileged institution in England. The richest and most noble people of the country trust him with their sons. Three weeks ago, the Duke of Holderness handed over to him through Secretary James Wilder his only son, Lord Saltire. At home, the boy lived a hard life. His parents divorced, and his mother left for France. The boy was on the side of his mother and really yearned for her. Then his father put him in a boarding school, where the boy soon got accustomed and felt great.
A few days ago, the boy ran away. Inspection of his room showed that he did not go to bed, put on his school uniform and jumped out the window, although no traces were found on the ground. Having discovered the disappearance of the little lord, the director urgently called all the teachers of the boarding school.Only the German teacher Heidegger did not come. Having examined his room, they found an unmade bed and clothes lying on the floor. From the footprints on the ground it was clear that he, too, jumped out the window. Gone and his bike.
Heidegger joined a boarding school two years ago. His recommendations were excellent, but he was a silent person and did not use love among teachers or students. He did not teach Lord Saltire, and there was no connection between him and the boy. The duke’s estate is not far from the school, but the boy was not found there. The police reached a dead end, there was only hope for a great detective.
Sherlock Holmes finds out the details of what happened. It is unlikely that the boy decided to escape himself. No one had visited him the day before, but there was a letter from his father.
Sherlock Holmes and Dr. Watson arrive at the boarding school. There the duke himself meets them with his secretary. The secretary is unhappy that outsiders are involved in the matter without permission, but since the great detective is aware, it is foolish to refuse his help. Holmes is interested in the letter that the boy received. The duke confirms that he wrote a letter to his son, but there was nothing in him that could excite the boy and inspire him with the thought of running away. It was sent by the secretary along with the rest of the correspondence.
Having examined the rooms of the fugitives, the great detective is convinced that they jumped out of the window. Having studied the map of the area and interviewed people, Holmes decides that the fugitives had one way - to the north, where the duke's house is located behind a grove and marshy plain.Farms are scattered across the plain, and a hotel and church are located right there. In a gypsy camp on a plain, they find a boy’s cap, although the gypsies say that they found a cap and are not involved in the abduction.
A survey of the plain yields nothing. Traces of the fugitives are trampled by sheep and cows. Find the track of the bike, but it does not match the track of the Heidegger bike. With difficulty, Holmes discovers a second track, which is a track from the teacher’s bicycle, and blood stains. Walking along it, he finds a bicycle in the thicket, and nearby - half-dressed Heidegger with a broken skull.
The great detective recreates the picture of escape. The boy was dressed, therefore, he was preparing to escape. The teacher dressed in a hurry, which means he saw a boy running away and rushed after him in a hurry. He took the bike because the boy had some means of transportation. Having overtaken the fugitive, the man received a fatal blow to the head, which only an adult could inflict. So the boy was not alone. Here Holmes is at a loss: around there are only traces of cows, and there are no human traces anywhere.
Holmes decides to follow the first track. He comes to a small hotel. Pretending to have twisted his leg, he asks the innkeeper to provide him with some kind of crew. The owner, who is not distinguished by courtesy, refuses, but hearing that he will be paid well, he promises to give horses. At the hotel, Holmes sees a forge. It seems strange to him that everywhere there are traces of cow hooves, but cows are nowhere to be seen. And what kind of cow walks at a trot, gallop and gallop? A great detective examines the hooves of horses, which infuriates the innkeeper.
Holmes decides to watch the hotel and sees the Duke's secretary on a bicycle.The secretary enters the hotel, and soon a crew departs from there, in which one person sits. The secretary himself remains near the hotel. After examining his bicycle, the great detective discovers that it was these tires that left marks on the plain.
The next day, Holmes arrives at the Duke. He asks the secretary to leave and reports that the duke’s son is in the hotel, the duke is the kidnapper, and the teacher’s killer is the innkeeper.
Once the duke fell in love with a woman, a marriage with which could ruin his career. The woman died, leaving him a child. The duke took care of him as much as he could, but could not openly acknowledge his paternity. He made the illegitimate son his secretary. When little Lord Saltier was born, James fiercely hated the rightful heir. He also influenced the break of the duke with his wife. The duke sent his youngest son to a boarding school, but James conceived the abduction, making his innkeeper an accomplice.
James put a note in the letter that the duke wrote to his son. In it, he asked the boy to meet with him in the grove, allegedly in order to convey something from his mother to him. The boy came to the grove, but there he met the owner of the hotel, who was on a horse, and for the boy he brought a pony. Seeing that the teacher was chasing them, the innkeeper hit him on the head, and brought the boy to himself and entrusted his wife with the cares. The duke knew nothing about this, but James began to demand that all property be left to him in exchange for his son. Then it became known about the death of the teacher. James got scared and asked his father for a few days so that the killer could hide.
After waiting for the darkness, the duke hastened to his son. The boy was safe and sound, but the murder made a terrible impression on him. While the boy is in the hotel, but the duke is at a loss: an investigation into the murder will lead to James. The Duke intends to send James to Australia and try to make peace with his wife.
Holmes is interested in two questions. The second - who thought the owner of the hotel to horseshoe so that their tracks could be mistaken for a cow? The duke explains that this method was used as far back as the Middle Ages to confuse traces during the chase. But what is the first question of the great detective? In response, Holmes takes a check with the remuneration due to him.