Sherlock Holmes is a government official. Mycroft has a unique civil service position as a kind of human database for all aspects of government policy. He lacks Sherlock's interest in physical investigation, however, preferring to spend his time at the Diogenes Club. Holmes says that he first developed his methods of deduction as an undergraduate; his earliest cases, which he pursued as an amateur, came from fellow university students. A meeting with a classmate's father led him to adopt detection as a profession, and he spent several years after university as a consultant before financial difficulties led him to accept John H.
Minor Sherlock Holmes characters their relationship. She also posed as John Watson's therapist and then later revealed herself to be Eurus Holmes, and at the end of the episode shoots John Watson with a handgun. In the last episode, "The Final Problem", it is revealed that Sherrinford is in fact a high-security complex on an island to house some of the most dangerous criminals in the world, including Eurus. With Eurus having simply shot John with a tranquiliser dart, Sherlock and John stage a scenario where Mycroft will admit Eurus's existence. Mycroft explains that Eurus was the youngest child, 8 years younger than Mycroft