The Blind Banker (S01E02)

Strange symbols have begun appearing on walls throughout London, and the first individual to decipher them meets a grim fate just hours later. Sherlock Holmes dives headfirst into this enigma, reaching out to the city's top graffiti artists for insights. As he delves deeper, he uncovers that a notorious gang of international smugglers, known as the Black Lotus, is behind the cryptic messages that have the city in their clutches.