The novel is set during the Reign of Terror following the start of the French Revolution. The title is the nom de guerre of its hero and protagonist, a chivalrous Englishman who rescues aristocrats before they are sent to the guillotine. Sir Percy Blakeney leads a double life: apparently nothing more than a wealthy fop, but in reality a formidable swordsman and a quick-thinking master of disguise and escape artist. The band of gentlemen who assist him are the only ones who know of his secret identity. He is known by his symbol, a simple flower, the scarlet pimpernel (Anagallis arvensis).