In 1525, on the evening of the Battle of Pavia, François 1er was taken prisoner by the armies of Charles-Quint, with the Constable de Bourbon on their side. His mother, regent of the kingdom, commissioned the king's loyal equerry, Antoine de Montpezat, to raise a ransom of two million ecus and send it to Madrid. Despite the treachery of Vandoeuvre, governor of Languedoc and supporter of the connétable de Bourbon, who has his eye on the French throne, Montpezat accomplishes his mission and is reunited with his fiancée, who had almost married the traitor Vandoeuvre.