At the court of Henry II, dominated by his wife, Caterina dei Medici, intrigue reigns.

In the southern provinces the Huguenots try to undermine the King's authority by any means, pushing the nobles to escape central power.

In the Dauphiné the Duke of Vars tries to draw from the situation to satisfy his ambitious aims: he would like to take over the region and marry Louise of Valency: But the girl hates him and when, after years of absence, Riccardo returns home, back from wars of Spain, she invites him to fight with her against the Duke.

Riccardo returned to sell his lands, having decided to move to Paris; but the love for his old childhood companion distracts him from his purpose.

To the power of the Duke he opposes his cunning and his courage: four comrades in arms help him in the fight against the tyrant, whom Riccardo eventually kills after a fierce duel.