Plot synopsis: In the 17th century, under Louis XIII, the policy of Cardinal de Richelieu aimed at the definitive establishment of a monarchic power, and gave rise to a struggle against the great feudal lords, who favored a weak central power. Numerous conspiracies against the Cardinal were led by the high nobility. The one led by Henri Coiffier de Ruzé d'Effiat, marquis de Cinq-Mars, was the last and most famous of them.