“A fourth action-filled puzzler for teen Sherlock as he plunges into a fight for his life and battles to discover what has happened to his missing friends”–
- ISBN: 9780374323110
- Published: 2013 , Farrar Straus & Giroux (J)
- Themes: action and adventure, Europe, Mystery and Thriller, Sherlock Holmes
- Descriptors: England (UK), Mystery and Thriller, Young Adult (ages 14-18)