"The First Sir Percy" is a sequel to The Laughing Cavalier, occurring a few months after the events in the first book. It is March 1624 in Holland. Two months earlier, a mercenary who calls himself "Diogenes" foiled the plot on the life of the Stadtholder, Prince of Orange. Now, he has finally met his real father, an English nobleman, and realized his true identity as Sir Percy Blake of Blakeney, heir to a large estate in Sussex. "The Laughing Cavalier" revolves around Percy Blake, a foreign adventurer and ancestor of the famous Scarlet Pimpernel. In March 1623, the Dutch nobleman Willem, Lord of Stoutenburg, is on the run. His father, the statesman Johan was falsely accused of treason and sent to the gallows by the Stadtholder, Prince of Orange. Willem's brother Reinier has since been arrested and executed for plotting to kill the Prince. Stoutenburg is now a fugitive and determined to get his revenge.