Final answer:
The Scarlet Pimpernel is set during the Reign of Terror in the French Revolution, late 18th century. The novel's plot revolves around the protagonist's efforts to save nobles from execution during this period of political upheaval and societal change.
Step-by-step explanation:
The novel The Scarlet Pimpernel takes place during the Reign of Terror in the French Revolution, which is specifically the late 18th century. This era is marked by the radical transformation of French society and the establishment of the First French Republic, with the overthrow of the monarchy. In the setting of The Scarlet Pimpernel, nobles are trying to escape the widespread executions and political chaos that are defining characteristics of this period. The protagonist, Sir Percy Blakeney, known by his moniker 'The Scarlet Pimpernel,' is covertly rescuing these nobles from the guillotine. The actions and the backdrop of the novel offer a dramatic and romanticized view of this tumultuous time in French history.