The war lords 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 a brilliant radar scientist, Joan Hughes, who has been 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".
| Writing | Sol Shor | Writer |
| Writing | Royal K. Cole | Writer |
| Camera | Ellis W. Carter | Director of Photography |
| Directing | Fred C. Brannon | Director |
| Art | Fred A. Ritter | Art Direction |
| Production | Franklin Adreon | Associate Producer |
| Writing | William Lively | Writer |
