A Study in Scarlet

The story begins with Dr. John Watson, a former army surgeon recently returned to London after serving in Afghanistan. He is in need of affordable lodgings and is introduced to Sherlock Holmes, a brilliant but eccentric consulting detective.
Holmes invites Watson to share a flat with him at 221B Baker Street, and the two quickly become friends. Watson is intrigued by Holmes's incredible deductive reasoning and keen sense of observation. Soon, they are embroiled in their first case together: the murder of Enoch Drebber and Joseph Stangerson, both Americans with mysterious backgrounds.
Holmes's deductive skills shine as he investigates the crime scene and uncovers crucial evidence. The trail leads them into the heart of London's criminal underworld and eventually to the solution of the murder mystery.