 Chapter titles: 1. The Great Secret 2. Marked for Death 3. The Gas  Chamber 4. Below the Waterline 5. The Acid Bath 6. The Unknown 7.  The Betrayal 8. A Crippled Hand 9. Woes of Deceit 10. The Inn of  Dread 11. The Death Studio 12. The Chance Trail 13. Wings of Mystery  14. The Hidden Way 15. The Secret Host