Trivia

The Mask, the villain of this serial, was the longest-running foe of Spy Smasher. Unfortunately, by the time the serial was made, the Mask was already dead - he had been strangled to death by Spy Smasher after he had exposed him to his "brainograph" machine and ordered Spy Smasher to "Kill!"

Screenwriters at the Republic Studios gave the Spy Smasher character a twin brother, a character which did not appear in the original comic strips.

Chapter Titles:

• 1. America Beware
• 2. Human Target
• 3. Iron Coffin
• 4. Stratosphere Invaiders
• 5. Descending Doom
• 6. The Invisible Witness
• 7. Secret Weapon
• 8. Sea Raiders
• 9. Highway Racketeers
• 10. 2700° Fahrenheit
• 11. Hero's Death
• 12. V...

The Mask was one of the few comic book/strip foes to appear in a serial. Except for Ming the Merciless, Luthor in Superman vs. Atom Man, and Laska/Leska from Blackhawk#31 in Blackhawk, very few serial adaptations featured foes from the original strips.

Half-way through the serial, the bad guys pass through a phony billboard advertising the Dick Tracy serials, also made by Republic.