David March is an agent with Blue Light.
As the Nazis in Germany were beginning their massive build-up to take on the rest of Europe, America was publicly maintaining a neutral position but some in the government were certain that the U.S. would be pulled into the upcoming conflict just as it eventually was in World War One. To help from within, as well as report from inside the likely enemy camp, officials in American Intelligence created the Blue Light program. Eighteen people from different walks of life were implanted into Germany to become part of the "other side", hopefully working their way into high levels in government and the media.
David March was a noted journalist who volunteered to be one of that eighteen. This meant that the handsome, well respected reporter would have to espouse a set of beliefs he decidedly did not feel himself so as to be seen firmly in the fascist camp. Since only a small handful of those in charge back home in the States knew the truth, March was made a pariah to most of its citizens. Even the woman that he was in love with did not know the truth and apparently committed suicide in anguish over the 'betrayal'.
We are told at the start of each of the episodic adventures concerning this individual, "American correspondent David March fled to Germany posing as a traitor to his own country. Accepted by the High Command, March worked as a double agent to destroy the Third Reich from within under the codename Blue Light."
In his new role as an American firmly in the Nazi camp, March is used primarily as a broadcaster and reporter on behalf of Hitler and his minions. However there are several instances where the Germans asked March to take a more active role in affairs and actually function as a spy on their behalf. This will present a major issue for March's safety since none of the Allied people he might come into contact with believe that March is a traitor to America and should be treated as such.
Working 'with' him is Suzanne Duchard. She is a French member of the notorious Gestapo, at least as far as that organization believes. It is her job to keep a close eye on March just in chase he should revert in his stated views. In truth she is working, like he, on the Allied side and not only tries to assist him in his various missions, she goes so far as to fall in love with him. This is interesting since publicly she tries to show how much she hates him.