El Dorado is a historical espionage novel. The story is set in Paris after the French Revolution and the guillotine horrors. The plot begins when Sir Percy, the Scarlet Pimpernel, unwillingly agrees to take Armand St. Just, brother of his wife, Marguerite, with him to France as part of a plan to save the young Dauphin. Percy warns Armand not to renew any friendships while in Paris, but it doesn't take long before Armand has ignored his warnings and renewed a friendship with the devious Baron de Batz, who wants to free the Dauphin himself and hates the Scarlet Pimpernel and all he represents...