Radar Patrol vs. Spy King (1949)

The warlords of a potential enemy of the US has the spy ring, led by John Baroda, the Spy King, and his aide Nitra, sabotaging the plans for a vast defense system of radar stations along the American borders. Radar Defense Bureau operative Chris Calvert comes to the rescue of brilliant radar scientist Joan Hughes, who was kidnapped by Baroda henchmen in chapter 1 ("The Fatal Fog"), and the two battle together before putting an end to the Spy King in the aptly-named chapter 12, "Day of Reckoning".