A former opera singer and actress, Irene Adler engaged in a brief affair with the King of Bohemia. Upon becoming engaged to a Scandinavian princess, the King enlists Sherlock Holmes to retrieve evidence of his tryst with Adler lest she use it to blackmail him and ruin his marriage before it begins. Holmes and Watson pursue Adler to the best of their abilities, but for the first time are outwitted themselves as Irene evades capture and leaves the country.