Following the Trail of Irene Adler's Sister

Sherlock Holmes knows that Irene Adler and Godfrey Norton didn't escape the island alone. He realizes that behind Irene Adler's blackmail and extortion there is a mastermind whose handwriting is remarkably similar to hers.However, this mysterious woman, whom no police officer has been able to identify because she possesses multiple identities and disguises, in many ways, is a very dangerous crimin...