The affair of the poisons continues. Could it even reach deep into Louis's own court?

Duchess Henriette becomes suddenly ill when she returns from a visit to her brother in England. They fear she might have been poisoned, so King Louis XIV shuts all access To Versailles.

Maintenon returns to the palace and encourages Louis to put his plans into action. Louis wants to discredit Leopold, and makes a secret pact with Barek, the Ottoman emissary. Philippe understands that the Church is at the origin of the conspiracy of the man in the iron mask, and suspects Louis to take part. Marie-Thérèse falls seriously ill.

The burning question remains: who is the man with the iron mask? Leto decides to bring the man with the iron mask to Versailles, but Bontemps feels the danger. With the help of Fabien, he removes the prisoner and brings him to Louis and Philippe. The truth is finally revealed.

After crushing the Protestants and thwarted Leto, Louis feels invincible. But his family and France are divided. What to expect from the future? What will be his legacy? Louis summons the Dauphin to show him how to be a good king. Louis decides to go to Paris to bless the sick. He does not know that the rebels fomented an attack for the murder...

While Philippe wants to send the man with the iron mask to the colonies, Louis knows that it must be eliminated. Meanwhile, the revolt rages in the streets of Paris, and the loyalty of Fabien is put to the test in the face of the violence of the King. Leto takes advantage of Louis' weakness and the threat of excommunication.

Louis has Phillipe get close to the spy. This ignites the Chevalier's jealousy. Fabien learns what Father Etienne does with the children he rescues. Montespan is desperate to reclaim the king's love, but Louis falls for someone more pious.

Fabien knows Louis has killed the prisoner and deduces the truth about the Man in the Iron Mask. Philippe decides to leave the court. Leto convinces Maintenon to support the marriage of Louis and the Infanta Isabella. But against all odds, Louis marries Maintenon and proclaims himself head of the Church of France. Louis accelerates his campaign of expansion in Europe and persecutes the Protestants.

Louis has Marie-Therese confined to the castle, suspecting her of conspiring against him with Leopold. Louis raises indignation by imprisoning a prominent Protestant philosopher. In Paris, Fabien is released in exchange for prisoners, but Louis asserts his authority by having one of them executed as an example.

In 1667 in France, Louis XIV is a young king who wants to impose his power whereas he is traumatized by the Fronde (the revolt of nobility during Louis XIII's reign) and despite the attacks of conspirators. Then, Louis XIV decides to establish the seat of the power out of Paris, in Versailles. At that time, Versailles is just a hunting lodge but Louis XIV radically wants to transform this castle.

Cassel's brigands continue to slaughter visitors to Versailles including the king's god-daughter though Fabien has his suspicions as to their identity and arrests a likely suspect, aiming to trap the murderers. Philippe is declared a hero, following his actions at the siege of Cambrai and Louis sends his brother's lover the Chevalier to join him though not before Chevalier has played the king's mistresses against him as several ambitious women arrive at court. Louis visits his brother on the eve of a battle and is taught that, of the two of them, Philippe is clearly the better soldier.

The Queen gave birth to the first royal baby and it triggers some rumors. Besides, Louis XIV's counselors advice him to go to war in order to impose his power. Furthermore, Louis XIV's brother Philippe dreams of glory and wants to be on the field of the future battles.

Ex-soldiers working on construction at the palace feel aggrieved at their treatment and down tools. On advice from gardener and confidant Jacques, who suggests a war hero act as intermediary, Louis is nonetheless jealously intransigent when Philippe offers his services. The king's bullying also extends to his refusal to allow ex-mistress Louise de la Valliere to leave for a convent whilst Athenais conducts her own agenda and Cassel, his home burned to the ground, is forced to move into the palace from where he continues to scheme. Louis is ultimately forced to bring Philippe in for a public relations exercise as he breaks the strike, after which Philippe makes his own plans to leave Versailles.

Though his palace continues to expand and receive admiration from around the world, Louis is still plagued by nightmares.

Madeleine de Foix is arrested as the poisoner after trying to kill Fabien. Montespans baby suffers an illness. Louis faces criticism from Bossuet and Pascal. Sophie endures a terrifying experience when married to Cassel.

Louis XIV wants the nobility to live at his side in Versailles. But noblemen and noblewomen have to prove their noble origin to obtain this privilege. Montcourt is one of them, but he can't prove his noble rank. Then, Montcourt meets a strange Duke called Cassel to help him. Besides, Louis XIV asks the Queen to welcome Annaba, an African prince.

King Louis XIV's continued insomnia makes him increasingly volatile, meaning Marchal's loyalty counts for nothing. Claudine continues to investigate the mystery toxin, while Sophie seeks a solution to her situation.

The King's bed example is blamed for the nobility's immorality, fuelled by illicit love potions and powders. Philippe must meet his new bride. Another victim of poisoning confounds Marchal.