The novel of "The Iron King" by Maurice Druon is the first in a cycle of seven books "The Accursed Kings" which chronicle the formation of the Nation state of France from the early Fourteenth Century onwards.

The tale of the "Iron King" concerns itself with the reign of King Philip IV (or Philip the Fair, known for his outstanding handsomeness). Philip the Fair was an autocratic ruler, a widower and the father of four children, Isabella, Louis, Philippe and Charles. Isabella is now, at the start of the book the Queen of England and has been locked into a loveless marriage with King Edward the Second. Philip the fair's three younger sons are all princes of the realm and married to the ladies of Burgundy; Beatrice, Jeanne, and Blanche.

The novel starts with the Chevalier Robert of Artois plotting with Queen Isabella to bring down the princesses of France. Having recently discovered that they are adulterous, he realizes that he can use this fact to bring down their family of Burgundy and the real object of his hatred — their mother Mahaut and his own Aunt. He desires this because Mahaut received lands as a dowry for marrying into the royal family, and he wishes to regai the lands of Burgundy and everything that his family had lost. Robert Artois manipulates Queen Isabella into a plot which will uncover the Princesses and demand the King of France takes action against them.

Meanwhile, Philip the Fair has also just completed his persecution of the Knight's Templar order; claiming that they are heretics and seizing from them their vast supplies of gold and holy artifacts from the Holy Lands of Jerusalem and the Middle East. As the last Grand Master of the Order, Jacques du Molay, dies he utters a curse that will fall upon the French Kingdom throughout the rest of this book and the later six novels.

The rest of the book concerns itself with the plot of Artois and the threat of the curse working itself out; as first one, then another character is poisoned, assassinated or seemingly dies of natural causes. The Kingdom of France is brought to near ruin and saved only by the Lombard Bankers (the leading families of Siennese merchants and gold speculators) who hold the fate of France in their grasp.