The Greek Interpreter by Arthur Conan Doyle

Holmes introduces Watson to his brilliant but eccentric brother Mycroft, who brings them a case involving a kidnapped Greek man forced to translate under threat. Holmes investigates and narrowly prevents a murder, though the main villains vanish. The plot centers on international intrigue, family loyalty, and clever observation. Mycroft’s brief appearance adds depth to Holmes’s world. It’s a tense and fast-moving case involving both intellect and danger.