"Blonde Venus" opens with the idealized courtship and marriage of Dietrich and mild-mannered chemist Herbert Marshall. Quickly ensconced as a Brooklyn, New York housewife and burdened with an impish son Dickie Moore, she is compelled to make herself a mistress to politico and nightclub gangster Cary Grant when her husband requires expensive medical treatment for radiation exposure. The plot grows increasingly improbable as Dietrich resurrects her theatrical career that takes to exotic locations around the world – with her little boy in tow.