A young man, Mr. Bennet, who is an assistant to the famous professor Presbury and the groom of his only daughter, turns to Sherlock Holmes for help.
Professor Presby, the famous European scientist, whose life is the first place in science, is a widower with an impeccable reputation. A few months ago, a professor who turned sixty-one, with ardent passion of a young man, made an offer to his colleague’s daughter. He liked the girl, but his age was interfering. At about the same time the professor left and did not tell anyone where. His family accidentally found out that he was in Prague.
Upon returning with the professor, strange things began to happen. He received cross-mailed letters from London, which Mr. Bennet, the professor’s personal secretary, was forbidden
Together with Mr. Bennett, his fiancee, the daughter of a professor, comes to the detective, who tells that she was awakened by a dog’s barking last night. When she woke up, she looked out the window on the third floor and saw with horror in front of her father’s face. Dr. Watson, who is present here, is trying to determine which professors may have mental and physical illnesses. The whole point is that such strange things happen to him from time to time, but he is still in his right mind and reason.
The great detective decides to visit the professor under the pretext of the appointment. However, the professor remembers perfectly well that he did not appoint any meeting. Holmes inspects the house. Before the window of his daughter on the third floor, the professor could only get on the ivy and downpipe, which it is almost impossible
The great detective also finds out that the professor receives letters from London from a certain Czech Doraq. Drawing attention to the dates of receiving letters, Holmes notes that the attacks of the professor happen every nine days. Most likely, he takes some remedy that he recommended in Prague.
As soon as the professor receives another letter from London, Mr. Bennet tells Holmes, and the great detective with Dr. Watson arrives at the professor’s house. On the way Holmes suddenly remembers that the fingers of the professor’s fingers are thickened and calloused.
In the evening, hiding, Holmes and Watson see the professor coming out of the house, getting on all fours and coming to the wall, entwined with ivy. He quickly climbs the wall, flying from branch to branch. Going down, he again gets on all fours and goes home, but then his dog, breaking off the chain, rushes at him.
After giving the professor medical help, Holmes, Watson and Bennett open the box. There they discover a letter in which it is reported that the professor was offered to use anti-aging serum. But to those who try to put themselves above Mother Nature, it’s not hard to slide down.