CaseBook #2 in this exciting series gives Sherlock Holmes and the Baker Street Irregulars a most unusual case to crack! A young woman named Elsa Hoffman seeks out the detective when her aunt dies a mysterious death. When the gang starts investigating, seemingly real ghosts suddenly appear and Elsa is being followed by shady characters. Holmes must decide if he and his assistants can solve the case without facing mortal danger. Join the Irregulars for a mysterious and frightening adventure and decide if this is a case of the supernatural or more dark con men, thieves, and murderers!