Through information gleaned from a German source in his private intelligence network, Winston Churchill alerts his goddaughter, the adventure-seeking Hearst photojournalist Mattie McGary, to a major political scandal in 1934-a conspiracy between the notoriously anti-Semitic U.S. Army's Military Intelligence Division [MID] and the SS, Hitler's Praetorian Guard, to help the Nazis formulate a sustainable rationale for the legal persecution of Germany's Jews. From Churchill, Mattie learns that the Nazis are working on new laws that strip Jews of their German citizenship and forbids them from marriage or sexual relations with Aryans. The year before, Reichsfuhrer-SS Heinrich Himmler, head of the SS, secretly arranged for the MID to research racist laws in thirty American states that prohibit marriage or sex between whites and a wide variety of other races. Radical SS anti-Semites intend to use that legal research-known in Germany as 'The Prussian Memorandum', an actual historic document-to provide a model for their proposed treatment of the Jews.

Aided by a courageous German lawyer, Hanna Raeder, wife of Admiral Erich Raeder, Chief of the German Navy since 1928, as well as her husband the New York lawyer Bourke Cockran, Jr., a former agent for MID, Mattie's efforts to document and expose the conspiracy take her from Churchill's country home in England to the corridors of power in Berlin and, along with Churchill, to the canals of Amsterdam where his German source is to provide them with conclusive proof of the conspiracy. Pursued by both Gestapo and American MID agents determined to stop them at all costs, Mattie, Hanna and Cockran race to expose the shameful secret of the Prussian Memorandum.

In a chilling climax, Mattie and Hanna are arrested and taken to a Gestapo-run concentration camp where Hanna is tortured and charged with treason and Mattie is charged with espionage. Both are scheduled for show trials the next day before the notorious "People's Court" where no one has ever been acquitted and the sentence upon conviction is death by beheading.

With additional historical supporting characters [in order of appearance] President Franklin D. Roosevelt, Secretary to the President Louis Howe, FBI Director J. Edgar Hoover, German Minister of Justice Franz Gurtner, Irish Blue Shirts leader General Eoin O'Duffy, New York attorney and Medal of Honor hero William 'Wild Bill' Donovan, Nazi Propaganda Minister Joseph Goebbel's wife Magda Goebbels, President of the Reichstag and Nazi Air Minister Hermann Goering, American media magnate William Randolph Hearst, Chief Judge of the Nazi People's Court Roland Freisler, Broadway investor and stage and screen star Mae West, New York mob boss Owney Madden, SD Foreign Intelligence head Walter Schellenberg, Cleveland attorney Paul Walter, Berlin Jewish journalist Bella Fromm, Harvard Law School Dean Roscoe Pound, Nazi Propaganda Minister Joseph Goebbels, and German Chancellor Adolf Hitler, The Prussian Memorandum is an authentic, action-packed historical adventure based on actual events.