Under the reign of Louis XV, corruption and intrigue have been allowed to blossom in France. Lord Justin Alastair, the notorious Duke of Avon, is known for his coldness of manner, his remarkable omniscience, and his debauched lifestyle. Society believes the worst of Justin, who is clearly proud of his sobriquet, 'Satanas'.

In a dark Parisian back alley, he is accosted by Leon, a young person dressed in ragged boy's clothing, running away from a brutal rustic guardian. The Duke buys Leon, a redheaded urchin with strangely familiar looks, who is, in fact, Leonie. She serves him with deep devotion.

Among the splendours of Versailles and the dignified mansions of Georgian England, Justin begins to unfold his sinister plans. Leonie plays a fine part in the Duke's long-overdue schemes to avenge himself on the Comte de St Vire. The Duke's plan is simple: parade delicately handsome Leonie in front of his enemy and transform her into the toast of the town, before reclaiming her birthright and destroying her true father in the process.

But the Duke hadn't expected Leonie's breathtaking transformation or the tender emotions she awakened. And he'd already set his dangerous scheme in motion...