Alan Armstrong (Kane Richmond) as the Spy Smasher is a costumed vigilante and freelance agent, not associated with the US government as the country has not yet joined its allies in World War II.

After discovering information about Nazi activities in occupied France, he is captured and ordered to be executed, but with the help of Pierre Durand (Franco Corsaro), he escapes back to the United States, meeting with his twin brother Jack (Kane Richmond).

Constant defeats at the hands of Spy Smasher, with support from Jack Armstrong and Admiral Corby (Sam Flint), also leads the villain to take the fight back to the masked hero.

[1] In the opinion of film historians Harmon and Glut, Spy Smasher is the best serial in terms of special effects and stunts, and one of the best in general; they described it as the foremost cliffhanger example of a whole school of Hollywood filmmaking of the 40s.

[6] Grant Tracey, writing on the Images Journal website, called Spy Smasher one of the best serials of all time due its stunning cliffhangers and unique innovations.

[7] In the 2005 episode of the animated series Justice League Unlimited entitled "Patriot Act", Spy Smasher appears in a World War II flashback.

The plot is unconnected to this serial, as Spy Smasher is shown preventing the creation of Fawcett Comics supervillain, Captain Nazi.

The style of the scene is based on a movie serial - it is drawn in black and white with similar action and background music.