Sherlock Holmes is a private investigator who works from his home on Baker Street in central London. A devoted pupil of crime studies, he is a zealous believer in the powers of observation and deductive reasoning. Holmes is typically unflappable and reserved, but on occasion he exposes a passionate, creative side. He has no interest in being a part of London society; apart from his relationship with Dr. John Watson, he is something of a loner. He has a renowned reputation, and has been commissioned to tackle cases all over the world.
Dr. John Watson
Dr. John Watson is Sherlock Holmes's best friend and frequent sidekick. His medical practice isn't very busy, which allows him time to tag along with Holmes during his various crime-solving adventures. Watson is good-natured and smart, but he (like many others) frequently misses clues that are easily detectable to Sherlock Holmes.
Though she was born in the United States, Irene Adler's opera career has taken her around Europe, where she meets the King of Bohemia and begins a romantic relationship with him. Her anger at the king causes her to make a rash decision, but she is otherwise poised and shrewd—so much so, in fact, she gets the better of Holmes and the king when they come looking for the photos she holds of her ex-lover.
Lestrade is a long-serving investigator at Scotland Yard, the police force of the city of London, but his main role is foil to Sherlock Holmes, who frequently exposes his incompetence. He represents the establishment, and accordingly he is conventional in every way—including his thinking. He has a prominent role in "The Boscombe Valley Mystery" and "The Adventure of the Noble Bachelor."