MASKED MARVEL 1942 serial

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In The Masked Marvel, a hero dressed in a business suit and a face mask fights the Japanese saboteur Sakima and his espionage organization. The hook of the story is that, in a reversal of the common serial "Masked Mystery Villain" stock character, the audience doesn't know who the hero is until the final reel—all the audience is told is that The Masked Marvel is one of a group of special investigators,