 He is the mastermind in the plot to kidnap Marie Antoinette before she could marry prince Louis XVI, but after it failed thanks to Lady Oscar's intervention, he tried to kill the Prince and make it seem like an accident by switching the rifle Prince Louis XVI used for hunting with a tampered one that would explode once triggered.Later in the story, Duke de Orleans, because of his liberal ideas, lets anti-monarchists like the Black Knight (a masked French Robin Hood) and his followers secretly gather in his Palais Royale.He, masked, helped Jeanne of Valois-Saint-Rémy, the mastermind of the Affair of the Diamond Necklace, to escape from Pitié-Salpêtrière Hospital's prison to a convent.