The Secret Code COMPLETE S01
https://www.imdb.com/title/tt0035299/
A police detective goes undercover and joins a gang of Nazi agents using explosive gases and artificial lightning to sabotage the war effort, whom he battles in disguise as The Black Commando.
Note: Each chapter ended with a quick lesson in cryptography and a "brief
patriotic admonishment" given by Selmer Jackson who played Major Henry
Barton.
