In the late 18th century, the French republic has been thrown into social and political chaos, a disarray that is exploited by the evil Maximillan Robespierre (Richard Basehart). Within 48 hours, Robespierre will sieze power and perpetrate his diabolicaltactics on France's helpless citizens. Charles (Robert Cummings), a freedom-fighter working for the resistance, poses as the murderous prosecutor that Robespierre has sent for, skillfully sidestepping the secret police and informants with the guidance ofMadelon (Arlene Dahl), a former lover who's now a key resistance member. When Robespierre tells Charles that his black book, a notorious death list filled with enemies on both sides, is missing, Charles is commanded to find it before its contents can be exposed, putting an end to his planned dictatorship. Charles' quest to maintain Robespierre's trust while secretly trying to destroy him and his wrathful allies elicits a series of suspenseful exploits where danger looms around every Parisian corner.