In 18th-century Europe, a young gypsy named Joseph Balsamo sets out to avenge the injustices done to his family and kind by the nobility. Early in life, Joseph's mother is executed unjustly, fueling his desire for retribution and power. Fleeing into exile, he encounters Dr. Mesmer, a practitioner of a mysterious new scientific phenomenon called animal magnetism. Joseph becomes a dedicated student of Mesmer’s teaching, mastering hypnotism and manipulation, which he soon realizes can be powerful tools against those who wronged him. Reinventing himself as Count Cagliostro, he uses his newfound powers to enthrall wealthy patrons and influential figures across Europe.

As Count Cagliostro rises in influence, he becomes embroiled in complex intrigues within the French court. He befriends Lorenzo, an ambitious young diplomat, and his path crosses with the beautiful Lorenza, who becomes pivotal to his scheming. Secretly fueling discontent against the nobility, Cagliostro engineers a plan aimed at toppling the aristocracy using deceit and his mesmerizing talents. However, as he ascends to remarkable heights of power and deception, the risks grow ever larger. Tensions and distrust mount within the court; faced with increasing scrutiny, Cagliostro must navigate a treacherous world where alliances are fragile, and betrayal could be lurking around every corner.