 The serial sees Captain America, really District Attorney Grant Gardner, trying to thwart the plans of the Scarab, really museum curator Dr. Cyrus Maldor - especially regarding his attempts to acquire the "Dynamic Vibrator" and "Electronic Firebolt", devices that could be used as super-weapons.In a rare plot element for Republic, the secret identity of the villain is known to the audience from the beginning, if not to the characters in the serial.The studio's usual approach was the use of a mystery villain who was unmasked as one of the other supporting characters only in the final chapter.