Sir Arthur Conan Doyle's Sherlock Holmes and Dr. Watson are re-envisioned as African-Americans living in present-day Harlem. Watson, an Afghan war vet, works in an inner-city clinic; Holmes, a local P.I., takes unusual cases. When a case ends up in Watson's ER, the unlikely duo partner up to find a missing girl and fall into a labyrinth of drugs, guns, gangs and a 'M'urderous conspiracy.