An anonymous telegram brings strange news to Baker Street: there is an impostor Sherlock Holmes at work in New York City, solving cases and taking society by storm. The real Sherlock Holmes, fresh from an undercover mission for his enigmatic brother Mycroft, wastes no time in crossing the Atlantic to confront the charlatan. But he and Watson find more than they bargained for: the counterfeit Sherlock is nowhere to be found and his clients.