In central London, the narrator, John H. Watson, MD, stands in the main room of the flat he shares with Sherlock Holmes. He examines an engraved walking stick left by someone named James Mortimer while they were out. Watson tells Holmes he believes the stick belongs to an elderly man of medicine who received the item as a thank-you from appreciative associates—perhaps members of a hunting club. The stick is well worn, and Watson decides the gentleman must do a great deal of walking.

Holmes compliments his friend on his sleuthing and agrees that the stick belongs to a doctor who enjoys walking. However, Holmes believes the stick is a gift from a local hospital staff on the occasion of his departure, that the man owns a dog larger than a terrier but smaller than a mastiff, and that he is “amiable, unambitious, and absent-minded” (2): An amiable man gets testimonials, an unambitious one departs the city for the country, and a forgetful one leaves his stick instead of a calling card. The man’s dog has held the stick in its mouth; the bite marks suggest the animal’s size.

Watson looks up James Mortimer in his Medical Directory and finds a surgeon description matches Holmes’s deductions.