CHAPTER TITLES: 1. Arctic Intrigue; 2. Murder or Accident; 3. Fangs of Death; 4. Underground Inferno; 5. Pursuit to Destruction; 6. The Boat Trap; 7. Flames Versus Gun; 8. Highway of Horror; 9. Doomed Cargo; 10. Human Quarry; 11. Mechanical Homicide; 12. Cavern of Revenge.
Budgeted at $172,795 but final cost was $167,669 (i.e., $5,126 or 3%, under budget), making this the most under-budget of all serials produced by Republic.
Episode 10, "Human Quarry", is a budget-saving recap episode where sequences from previous chapters are shown for most of the running time.
Many of the scenes showing the dog sleds, river ice breaking, the two bear cubs, the dogs attacking deer and people, and the avalanche, are originally from the movie Call of the Yukon (1938).
The two bear cubs names are Toughie and Roughie.