Chapter titles: 1. Cave of Despair 2. The Spider's Web 3. The Mummy Man 4. The Death Trap 5. Trails of Treachery 6. Furnace of Fear 7. Brink of Eternity 8. Pit of Evil 9. The Opal Bracelet 10. In the Enemy's Hands 11. A Race with Death 12. The Bridge of Fear 13. The Hill of Horror 14. A Jest of Fate 15. A Conquest of Courage 16. Fire of Fury 17. The Wings of Destiny 18. The Avenging Conscience
This serial was based on the legend of a tribe of Indians in San Pedro who lived inside a mountain from which they left to tend their fields through a cunningly concealed door, then returned by night and closed the door behind them.