In 1465 Scotland, honorable knight Quentin Durward meets with his elderly uncle, the distinguished but impoverished Lord Crawford, who seeks to marry the young and wealthy Isabelle, Countess of Marcroy in France. Crawford requests that his nephew carry his proposal to France and also determine that Isabelle is worthy of the union. In France, at the Peronne chateau of Charles, Duke of Burgundy, the duke is angered when his ward Isabelle refuses to receive Lord Malcolm, the Scottish ambassador. Outraged that the duke has already approved of her marriage in order to secure the alliance with Crawford as well as to gain access to her great fortune and vast property, Isabelle rejects the proposed wedding. That evening, Quentin attends a banquet given by Charles in honor of Malcolm, but the festivities are interrupted by the news that Isabelle has run away. Learning that Isabelle's coach and guards have fled, Quentin follows. Later, Isabelle's coach makes a brief stop at an inn where a local man overhears mention of Isabelle's large jewelry box and reports the information to Count William de la Marck, a renegade aristocrat-turned-criminal, who rules the forest with a thousand men. Arriving at the inn after Isabelle's departure, Quentin discovers the countess is in danger and, outflanking the count's forces, reaches Isabelle's escort in time to warn them. With the assistance of Isabelle's guards, Quentin sets up an ambush for de la Marck and his men, allowing Isabelle to escape safely. After losing his horse in the attack, Quentin returns on foot to Malcolm, who suspects that Isabelle has sought refuge at the court of King Louis XI. Malcolm reveals if this is true, Charles will believe Isabelle has betrayed him and declare war on Louis to regain control of her lands. Malcolm beseeches Quentin to go to the French court for the good of Scotland's ally, Burgundy, warning him not to count on the principles of knightly honor, which have given way to violence and duplicity. Upon arriving at the chateau of King Louis in Plessis les Tours, Quentin is rebuffed by the palace guards when he requests an audience with the king. Later in the nearby forest, Quentin frees a gypsy who has been hung, but the man is then shot by several armed men. When the men's leader offers Quentin money to join them, Quentin berates him for his attempted bribery only to be shocked to learn the man is King Louis. Declaring that he cannot trust a man he cannot buy, Louis orders Quentin to depart France. That evening as Quentin lurks outside the king's castle, he is befriended by a gypsy, Hayraddin, the brother of the man killed in the forest. Hayraddin admits that he is a spy and acknowledges that Isabelle has indeed come to the castle, but is now being held under guard by Louis. Fearful that Quentin's virtuous behavior will place him in danger, Hayraddin urges Quentin to break into the castle while he distracts the guards. Once in the castle, Quentin sneaks into Louis' private chamber and demands that the king allow him to serve France. Impressed with Quentin's bravery and daring, Louis welcomes him and orders him to guard Isabelle. Unknown to Quentin, Louis then meets Charles's representative, Count Phillip de Creville, who demands that Isabelle be released. When Louis denies Isabelle's presence, de Creville declares Charles's intention to go to war unless the countess is returned. Louis offers Charles thirty days to reconsider and vows to come to Burgundy personally at the end of that time to negotiate with Charles. Privately, Louis assures his shocked advisors that he has no intention of going to Burgundy and intends to use de la Marck against Charles. Meanwhile, Isabelle takes a liking to Quentin who laments that the virtues of honor and decency have fallen out of fashion. Later in private, Louis tells Isabelle that her presence in the castle is too much of a danger and he can no longer protect her. Isabelle agrees to depart, declaring she will return to Burgundy to seek sanctuary with the Bishop of Liege. Louis promises her an escort through the dangerous Ardennes forest, but then secretly arranges with his confidant, Master Oliver, to have Hayraddin pay de la Marck to kidnap Isabelle to bring her back to his court. Louis then orders Quentin to lead Isabelle's escort guard to Liege. On the evening of the first day of travel, Isabelle grows suspicious of Quentin when he refuses to explain his relationship with Lord Crawford or his presence in France. The next day, Isabelle's coach loses a wheel and during the repair, she attempts to escape. Quentin catches her and confesses that despite having fallen in love with her, he is obliged to deliver her to Liege. Later, Hayraddin joins Isabelle's party as the guide promised by Louis. Realizing that Quentin is incapable of suspecting the king of duplicity, Hayraddin reveals the impending assault by de la Marck. When the count's men attack, Isabelle escapes her kidnappers and distracts the soldiers by throwing them her jewelry box. Quentin is wounded while escaping with Isabelle, and Hayraddin takes them to hide in a gypsy camp. Leaving the next morning so as not to endanger the gypsies, the group continues in disguise to Liege where the bishop welcomes Isabelle. Quentin recovers over the next few weeks, then admits his relationship with Crawford and Charles to Isabelle, who fears that Quentin's integrity will prevent any chance for their personal happiness. When the thirty-day period reaches an end, Charles is amazed that Louis comes to Burgundy as promised. On that same day, Hayraddin spots de la Marck's men at a Liege inn and on his way to advise Quentin, is shot and killed. In front of Charles and his court, Louis insists that he did not go against Burgundy by sheltering Isabelle. Meanwhile, de la Marck leads an attack on Liege and finding Isabelle, demands that the bishop marry them in order to disrupt Louis' plans and gain access to Isabelle's fortune and land for himself. Spotting the burning church walls, set on fire during the initial assault, Quentin arrives and rescues Isabelle before meeting de la Marck in a duel in a burning bell tower where the count is killed. Quentin returns to Perrone to discover from Malcolm that Crawford has unexpectedly died and that Charles has arrested Louis on the belief that he ordered the murder of the bishop. Quentin attends Louis' trial and presents de la Marck's severed head, swearing the count murdered the bishop and that he killed the count at Louis' behest to defend Isabelle, a citizen of Burgundy. Freed by the court, Louis then challenges Charles to work with him to create a united France. When the men then bicker about which of their lieutenants should marry Isabelle, Louis abruptly makes the radical suggestion that the countess be allowed to select her own husband. Isabelle joyfully chooses Quentin and the two are wed.
