On the evening of March 20, 1888, a masked gentleman calls on Sherlock Holmes at Baker Street and removes his disguise to reveal himself as Wilhelm von Ormstein, King of Bohemia. He needs Holmes to recover a compromising photograph held by the opera singer Irene Adler — a woman he was once involved with — before his forthcoming marriage to a Scandinavian princess. It is the case that introduces the only person Holmes ever consistently refers to as 'the woman.'