Chauvelin comes into possession of a note that indicates that Armand St. is working against the French government .
Marguerite is blackmailed by the wily new French envoy to England, Citizen Chauvelin. Chauvelin's agents have stolen a letter incriminating her beloved brother Armand, proving that he is in league with the Pimpernel. Chauvelin offers to trade Armand's life for her help against the Pimpernel. Contemptuous of her seemingly witless and unloving husband, Marguerite does not go to him for help or advice. Instead, she passes along information which enables Chauvelin to learn the Pimpernel's true identity.
Later that night, Marguerite finally tells her husband of the terrible danger threatening her brother and pleads for his assistance.
Percy promises to save him. After Percy unexpectedly leaves for France, Marguerite discovers to her horror that he is the Pimpernel. He had hidden behind the persona of a dull, slow-witted fop in order to deceive the world. He had not told Marguerite because of his worry that she might betray him, as she had the Marquis de St. Cyr. Desperate to save her husband, she pursues Percy to France to warn him that Chauvelin knows his identity and his purpose.
Percy openly approaches Chauvelin in a decrepit inn, but despite Chauvelin's best efforts, the Englishman manages to escape. Through a bold plan executed right under Chauvelin's nose, Percy rescues Marguerite's brother Armand and the Comte de Tournay, the father of a schoolfriend of Marguerite's. Marguerite pursues Percy right to the very end, resolute that she must either warn him or share his fate. That's it in a nutshell!
